Quickbooks Web Connector throwing Index was outside the bounds of the array

I am integrating quickbooks desktop with opencart using WCF services and Quickbooks web connector. but i am getting this error while calling authenticate method.

Here is my .cs Code

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;
using System.Text.RegularExpressions;
using System.Xml;
using Interop.QBPOSXMLRPLIB;

namespace QuickBookWebConnector
{
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "Service1" in code, svc and config file together.
    // NOTE: In order to launch WCF Test Client for testing this service, please select Service1.svc or Service1.svc.cs at the Solution Explorer and start debugging.
    public class Service1 : IService1
    {
        //public const string DATE_FORMAT = "yyyy-MM-ddTHH\\:mm\\:sszzz";
        System.Diagnostics.EventLog evLog = new System.Diagnostics.EventLog();
        public int count = 0;
        public ArrayList req = new ArrayList();
        public const string URL = "http://developer.intuit.com/";

        public Service1()
        {
            initEvLog();
        }

        public string clientVersion(string strVersion)
        {
            string evLogTxt = "WebMethod: clientVersion() has been called " +
                "by QBWebconnector" + "\r\n\r\n";
            evLogTxt = evLogTxt + "Parameters received:\r\n";
            evLogTxt = evLogTxt + "string strVersion = " + strVersion + "\r\n";
            evLogTxt = evLogTxt + "\r\n";

            string retVal = null;
            double recommendedVersion = 1.5;
            double supportedMinVersion = 1.0;
            double suppliedVersion = Convert.ToDouble(this.parseForVersion(strVersion));
            evLogTxt = evLogTxt + "QBWebConnector version = " + strVersion + "\r\n";
            evLogTxt = evLogTxt + "Recommended Version = " + recommendedVersion.ToString() + "\r\n";
            evLogTxt = evLogTxt + "Supported Minimum Version = " + supportedMinVersion.ToString() + "\r\n";
            evLogTxt = evLogTxt + "SuppliedVersion = " + suppliedVersion.ToString() + "\r\n";
            if (suppliedVersion < recommendedVersion)
            {
                retVal = "W:We recommend that you upgrade your QBWebConnector";
            }
            else if (suppliedVersion < supportedMinVersion)
            {
                retVal = "E:You need to upgrade your QBWebConnector";
            }
            evLogTxt = evLogTxt + "\r\n";
            evLogTxt = evLogTxt + "Return values: " + "\r\n";
            evLogTxt = evLogTxt + "string retVal = " + retVal;
            logEvent(evLogTxt);
            return retVal;
        }

        public string[] authenticate(string strUserName, string strPassword)
        {
            string evLogTxt = "WebMethod: authenticate() has been called by QBWebconnector" + "\r\n\r\n";
            evLogTxt = evLogTxt + "Parameters received:\r\n";
            evLogTxt = evLogTxt + "string strUserName = " + strUserName + "\r\n";
            evLogTxt = evLogTxt + "string strPassword = " + strPassword + "\r\n";
            evLogTxt = evLogTxt + "\r\n";


            string[] authReturn = new string[4];
            // Code below uses a random GUID to use as session ticket
            // An example of a GUID is {85B41BEE-5CD9-427a-A61B-83964F1EB426}
            authReturn[0] = System.Guid.NewGuid().ToString();

            // For simplicity of sample, a hardcoded username/password is used.
            // In real world, you should handle authentication in using a standard way. 
            // For example, you could validate the username/password against an LDAP 
            // or a directory server
            string pwd = "test";
            evLogTxt = evLogTxt + "Password locally stored = " + pwd + "\r\n";
            if (strUserName.Trim().Equals("Sysadmin") && strPassword.ToUpper().Trim().Equals(pwd.ToUpper()))
            {
                // An empty string for authReturn[1] means asking QBWebConnector 
                // to connect to the company file that is currently openned in QB
                authReturn[1] = "technics";
            }
            else
            {
                authReturn[1] = "nvu";
            }
            // You could also return "none" to indicate there is no work to do
            // or a company filename in the format C:\full\path\to\company.qbw
            // based on your program logic and requirements.

            authReturn[2] = "10";
            authReturn[3] = "20";

            evLogTxt = evLogTxt + "\r\n";
            evLogTxt = evLogTxt + "Return values: " + "\r\n";
            evLogTxt = evLogTxt + "string[] authReturn[0] = " + authReturn[0].ToString() + "\r\n";
            evLogTxt = evLogTxt + "string[] authReturn[1] = " + authReturn[1].ToString();
            evLogTxt = evLogTxt + "string[] authReturn[2] = " + authReturn[2].ToString();
            evLogTxt = evLogTxt + "string[] authReturn[3] = " + authReturn[3].ToString();
            logEvent(evLogTxt);
            return authReturn;
        }

        public string connectionError(string ticket, string hresult, string message)
        {
            //if (Session["ce_counter"] == null)
            //{
            //    Session["ce_counter"] = 0;
            //}

            string evLogTxt = "WebMethod: connectionError() has been called by QBWebconnector" + "\r\n\r\n";
            evLogTxt = evLogTxt + "Parameters received:\r\n";
            evLogTxt = evLogTxt + "string ticket = " + ticket + "\r\n";
            evLogTxt = evLogTxt + "string hresult = " + hresult + "\r\n";
            evLogTxt = evLogTxt + "string message = " + message + "\r\n";
            evLogTxt = evLogTxt + "\r\n";

            string retVal = null;
            //-2147418113 = Can't connect to the database
            const string CANT_CONNECT_TO_DB = "0x8000FFFF";
            // Add more as you need...

            if (hresult.Trim().Equals(CANT_CONNECT_TO_DB))
            {
                evLogTxt = evLogTxt + "HRESULT = " + hresult + "\r\n";
                evLogTxt = evLogTxt + "Message = " + message + "\r\n";
                retVal = "DONE";
            }
            else
            {
                //// Depending on various hresults return different value 
                //if ((int)Session["ce_counter"] == 0)
                //{
                //    // Try again with this company file
                //    evLogTxt = evLogTxt + "HRESULT = " + hresult + "\r\n";
                //    evLogTxt = evLogTxt + "Message = " + message + "\r\n";
                //    evLogTxt = evLogTxt + "Sending connection string as \"Company Data=\" to QBWebConnector.";
                //    retVal = "Company Data=";
                //}
                //else
                //{
                //    evLogTxt = evLogTxt + "HRESULT = " + hresult + "\r\n";
                //    evLogTxt = evLogTxt + "Message = " + message + "\r\n";
                //    evLogTxt = evLogTxt + "Sending DONE to stop.";
                //    retVal = "DONE";
                //}

                // Try again with this company file
                evLogTxt = evLogTxt + "HRESULT = " + hresult + "\r\n";
                evLogTxt = evLogTxt + "Message = " + message + "\r\n";
                evLogTxt = evLogTxt + "Sending connection string as \"Company Data=\" to QBWebConnector.";
                retVal = "Company Data=";
            }
            evLogTxt = evLogTxt + "\r\n";
            evLogTxt = evLogTxt + "Return values: " + "\r\n";
            evLogTxt = evLogTxt + "string retVal = " + retVal + "\r\n";
            logEvent(evLogTxt);
           // Session["ce_counter"] = ((int)Session["ce_counter"]) + 1;
            return retVal;
        }

        public string sendRequestXML(string ticket, string strHCPResponse, string strCompanyFileName,
            string qbXMLCountry, int qbXMLMajorVers, int qbXMLMinorVers)
        {
            //if (Session["counter"] == null)
            //{
            //    Session["counter"] = 0;
            //}
            string evLogTxt = "WebMethod: sendRequestXML() has been called by QBWebconnector" + "\r\n\r\n";
            evLogTxt = evLogTxt + "Parameters received:\r\n";
            evLogTxt = evLogTxt + "string ticket = " + ticket + "\r\n";
            evLogTxt = evLogTxt + "string strHCPResponse = " + strHCPResponse + "\r\n";
            evLogTxt = evLogTxt + "string strCompanyFileName = " + strCompanyFileName + "\r\n";
            evLogTxt = evLogTxt + "string qbXMLCountry = " + qbXMLCountry + "\r\n";
            evLogTxt = evLogTxt + "int qbXMLMajorVers = " + qbXMLMajorVers.ToString() + "\r\n";
            evLogTxt = evLogTxt + "int qbXMLMinorVers = " + qbXMLMinorVers.ToString() + "\r\n";
            evLogTxt = evLogTxt + "\r\n";

            ArrayList req = buildRequest();
            string request = "";
            int total = req.Count;
           // count = Convert.ToInt32(Session["counter"]);

            if (count < total)
            {
                request = req[count].ToString();
                evLogTxt = evLogTxt + "sending request no = " + (count + 1) + "\r\n";
                //Session["counter"] = ((int)Session["counter"]) + 1;
            }
            else
            {
                count = 0;
               // Session["counter"] = 0;
                request = "";
            }
            evLogTxt = evLogTxt + "\r\n";
            evLogTxt = evLogTxt + "Return values: " + "\r\n";
            evLogTxt = evLogTxt + "string request = " + request + "\r\n";
            logEvent(evLogTxt);
            return request;
        }

        public int receiveResponseXML(string ticket, string response, string hresult, string message)
        {
            string evLogTxt = "WebMethod: receiveResponseXML() has been called by QBWebconnector" + "\r\n\r\n";
            evLogTxt = evLogTxt + "Parameters received:\r\n";
            evLogTxt = evLogTxt + "string ticket = " + ticket + "\r\n";
            evLogTxt = evLogTxt + "string response = " + response + "\r\n";
            evLogTxt = evLogTxt + "string hresult = " + hresult + "\r\n";
            evLogTxt = evLogTxt + "string message = " + message + "\r\n";
            evLogTxt = evLogTxt + "\r\n";

            int retVal = 0;
            if (!hresult.ToString().Equals(""))
            {
                // if there is an error with response received, web service could also return a -ve int     
                evLogTxt = evLogTxt + "HRESULT = " + hresult + "\r\n";
                evLogTxt = evLogTxt + "Message = " + message + "\r\n";
                retVal = -101;
            }
            else
            {
                evLogTxt = evLogTxt + "Length of response received = " + response.Length + "\r\n";

                ArrayList req = buildRequest();
                int total = req.Count;
               // int count = Convert.ToInt32(Session["counter"]);

                int percentage = (count * 100) / total;
                if (percentage >= 100)
                {
                    count = 0;
                   // Session["counter"] = 0;
                }
                retVal = percentage;
            }
            evLogTxt = evLogTxt + "\r\n";
            evLogTxt = evLogTxt + "Return values: " + "\r\n";
            evLogTxt = evLogTxt + "int retVal= " + retVal.ToString() + "\r\n";
            logEvent(evLogTxt);
            return retVal;
        }

        public string getLastError(string ticket)
        {
            string evLogTxt = "WebMethod: getLastError() has been called by QBWebconnector" + "\r\n\r\n";
            evLogTxt = evLogTxt + "Parameters received:\r\n";
            evLogTxt = evLogTxt + "string ticket = " + ticket + "\r\n";
            evLogTxt = evLogTxt + "\r\n";

            int errorCode = 0;
            string retVal = null;
            if (errorCode == -101)
            {
                retVal = "QuickBooks was not running!"; // This is just an example of custom user errors
            }
            else
            {
                retVal = "Error!";
            }
            evLogTxt = evLogTxt + "\r\n";
            evLogTxt = evLogTxt + "Return values: " + "\r\n";
            evLogTxt = evLogTxt + "string retVal= " + retVal + "\r\n";
            logEvent(evLogTxt);
            return retVal;
        }

        public string closeConnection(string ticket)
        {
            string evLogTxt = "WebMethod: closeConnection() has been called by QBWebconnector" + "\r\n\r\n";
            evLogTxt = evLogTxt + "Parameters received:\r\n";
            evLogTxt = evLogTxt + "string ticket = " + ticket + "\r\n";
            evLogTxt = evLogTxt + "\r\n";
            string retVal = null;

            retVal = "OK";

            evLogTxt = evLogTxt + "\r\n";
            evLogTxt = evLogTxt + "Return values: " + "\r\n";
            evLogTxt = evLogTxt + "string retVal= " + retVal + "\r\n";
            logEvent(evLogTxt);
            return retVal;
        }


        #region UtilityMethods
        private void initEvLog()
        {
            try
            {
                string source = "WCWebService";
                if (!System.Diagnostics.EventLog.SourceExists(source))
                    System.Diagnostics.EventLog.CreateEventSource(source, "Application");
                evLog.Source = source;
            }
            catch(Exception ex)
            {

            };
            return;
        }

        private void logEvent(string logText)
        {
            try
            {
                evLog.WriteEntry(logText);
            }
            catch { };
            return;
        }

        public ArrayList buildRequest()
        {
            string strRequestXML = "";
            XmlDocument inputXMLDoc = null;

            // CustomerQuery
            inputXMLDoc = new XmlDocument();
            inputXMLDoc.AppendChild(inputXMLDoc.CreateXmlDeclaration("1.0", null, null));
            inputXMLDoc.AppendChild(inputXMLDoc.CreateProcessingInstruction("qbposxml", "version=\"1.0\""));

            XmlElement qbposXML = inputXMLDoc.CreateElement("QBPOSXML");
            inputXMLDoc.AppendChild(qbposXML);
            XmlElement qbposXMLMsgsRq = inputXMLDoc.CreateElement("QBPOSXMLMsgsRq");
            qbposXML.AppendChild(qbposXMLMsgsRq);
            qbposXMLMsgsRq.SetAttribute("onError", "stopOnError");
            XmlElement customerQueryRq = inputXMLDoc.CreateElement("CustomerQueryRq");
            qbposXMLMsgsRq.AppendChild(customerQueryRq);
            customerQueryRq.SetAttribute("requestID", "1");
            XmlElement maxReturned = inputXMLDoc.CreateElement("MaxReturned");
            customerQueryRq.AppendChild(maxReturned).InnerText = "1";

            strRequestXML = inputXMLDoc.OuterXml;
            req.Add(strRequestXML);

            // Clean up
            strRequestXML = "";
            inputXMLDoc = null;
            qbposXML = null;
            qbposXMLMsgsRq = null;
            maxReturned = null;

            // ItemInventoryQuery
            inputXMLDoc = new XmlDocument();
            inputXMLDoc.AppendChild(inputXMLDoc.CreateXmlDeclaration("1.0", null, null));
            inputXMLDoc.AppendChild(inputXMLDoc.CreateProcessingInstruction("qbposxml", "version=\"1.0\""));

            qbposXML = inputXMLDoc.CreateElement("QBPOSXML");
            inputXMLDoc.AppendChild(qbposXML);
            qbposXMLMsgsRq = inputXMLDoc.CreateElement("QBPOSXMLMsgsRq");
            qbposXML.AppendChild(qbposXMLMsgsRq);
            qbposXMLMsgsRq.SetAttribute("onError", "stopOnError");
            XmlElement itemInventoryQueryRq = inputXMLDoc.CreateElement("ItemInventoryQueryRq");
            qbposXMLMsgsRq.AppendChild(itemInventoryQueryRq);
            itemInventoryQueryRq.SetAttribute("requestID", "2");
            maxReturned = inputXMLDoc.CreateElement("MaxReturned");
            itemInventoryQueryRq.AppendChild(maxReturned).InnerText = "1";

            strRequestXML = inputXMLDoc.OuterXml;
            req.Add(strRequestXML);

            // Clean up
            strRequestXML = "";
            inputXMLDoc = null;
            qbposXML = null;
            qbposXMLMsgsRq = null;
            maxReturned = null;

            // PurchaseOrderQuery
            inputXMLDoc = new XmlDocument();
            inputXMLDoc.AppendChild(inputXMLDoc.CreateXmlDeclaration("1.0", null, null));
            inputXMLDoc.AppendChild(inputXMLDoc.CreateProcessingInstruction("qbposxml", "version=\"1.0\""));

            qbposXML = inputXMLDoc.CreateElement("QBPOSXML");
            inputXMLDoc.AppendChild(qbposXML);
            qbposXMLMsgsRq = inputXMLDoc.CreateElement("QBPOSXMLMsgsRq");
            qbposXML.AppendChild(qbposXMLMsgsRq);
            qbposXMLMsgsRq.SetAttribute("onError", "stopOnError");
            XmlElement purchaseOrderQueryRq = inputXMLDoc.CreateElement("PurchaseOrderQueryRq");
            qbposXMLMsgsRq.AppendChild(purchaseOrderQueryRq);
            purchaseOrderQueryRq.SetAttribute("requestID", "3");
            maxReturned = inputXMLDoc.CreateElement("MaxReturned");
            purchaseOrderQueryRq.AppendChild(maxReturned).InnerText = "1";

            strRequestXML = inputXMLDoc.OuterXml;
            req.Add(strRequestXML);

            return req;
        }

        private string parseForVersion(string input)
        {
            // This method is created just to parse the first two version components
            // out of the standard four component version number:
            // <Major>.<Minor>.<Release>.<Build>
            // 
            // As long as you get the version in right format, you could use
            // any algorithm here. 
            string retVal = "";
            string major = "";
            string minor = "";
            Regex version = new Regex(@"^(?<major>\d+)\.(?<minor>\d+)(\.\w+){0,2}$", RegexOptions.Compiled);
            Match versionMatch = version.Match(input);
            if (versionMatch.Success)
            {
                major = versionMatch.Result("${major}");
                minor = versionMatch.Result("${minor}");
                retVal = major + "." + minor;
            }
            else
            {
                retVal = input;
            }
            return retVal;
        }
        #endregion

    }
}

and this Configuration file Code:

   <?xml version="1.0"?>
<configuration>
  <appSettings/>
  <connectionStrings/>
  <!--
    For a description of web.config changes see http://go.microsoft.com/fwlink/?LinkId=235367.

    The following attributes can be set on the <httpRuntime> tag.
      <system.Web>
        <httpRuntime targetFramework="4.5.2" />
      </system.Web>
  -->
  <system.web>
    <compilation debug="true" targetFramework="4.5.2"/>
    <!--
        The <authentication> section enables configuration 
        of the security authentication mode used by 
        ASP.NET to identify an incoming user. 
    -->
    <authentication mode="Windows"/>
    <!--
        The <customErrors> section enables configuration 
        of what to do if/when an unhandled error occurs 
        during the execution of a request. Specifically, 
        it enables developers to configure html error pages 
        to be displayed in place of a error stack trace.

        <customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm">
         <error statusCode="403" redirect="NoAccess.htm" />
         <error statusCode="404" redirect="FileNotFound.htm" />
        </customErrors>
    -->
    <pages controlRenderingCompatibilityVersion="3.5" clientIDMode="AutoID"/>
  </system.web>
  <!-- 
      The system.webServer section is required for running ASP.NET AJAX under Internet
      Information Services 7.0.  It is not necessary for previous version of IIS.
  -->
  <system.webServer>
    <!--
        To browse web app root directory during debugging, set the value below to true.
        Set to false before deployment to avoid disclosing web app folder information.
      -->
    <directoryBrowse enabled="true"/>
  </system.webServer>
  <system.serviceModel>
    <services>
      <service name="QuickBookWebConnector.Service1" behaviorConfiguration="QuickBookWebConnector.Service1Behavior">
        <!-- Service Endpoints -->
        <endpoint address="" binding="basicHttpBinding" contract="QuickBookWebConnector.IService1">
          <!-- 
              Upon deployment, the following identity element should be removed or replaced to reflect the 
              identity under which the deployed service runs.  If removed, WCF will infer an appropriate identity 
              automatically.
          -->
          <identity>
            <dns value="localhost"/>
          </identity>
        </endpoint>
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="QuickBookWebConnector.Service1Behavior">
          <!-- To avoid disclosing metadata information, set the value below to false before deployment -->
          <serviceMetadata httpGetEnabled="true"/>
          <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->
          <serviceDebug includeExceptionDetailInFaults="false"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
  </system.serviceModel>
</configuration>

This is log file of web connector:

20170517.16:20:49 UTC   : QBWebConnector.CompanyFileLock.initialize() : Company file has been initialized with AppLock = UNLOCKED:MSIDDIQUI-LAPTO for ownerID = <{C4DD1DB4-E7DE-4B1E-B33D-D7F3EDC7D613}>
20170517.16:20:49 UTC   : QBWebConnector.SOAPWebService.AddToQuickBooks() : Application DebuggingService has been added to QuickBooks.
20170517.16:20:49 UTC   : QBWebConnector.SOAPWebService.DisconnectFromQB() : Session ended and connection closed
20170517.16:20:50 UTC   :  : ~SingleInstanceHandler() - usingInstanceChannel = false. Returning without any Registry key delete or unmarshalling.
20170517.16:20:56 UTC   : QBWebConnector.WebServiceManager.DoUpdateSelected() : updateWS() for application = 'DebuggingService' has STARTED
20170517.16:20:56 UTC   : QBWebConnector.RegistryManager.getUpdateLock() : HKEY_CURRENT_USER\Software\Intuit\QBWebConnector\UpdateLock = FALSE
20170517.16:20:56 UTC   : QBWebConnector.RegistryManager.setUpdateLock() : HKEY_CURRENT_USER\Software\Intuit\QBWebConnector\UpdateLock has been set to True
20170517.16:20:56 UTC   : QBWebConnector.RegistryManager.setUpdateLock() : ********************* Update session locked *********************
20170517.16:20:56 UTC   : QBWebConnector.SOAPWebService.instantiateWebService() : Initiated connection to the following application.
20170517.16:20:56 UTC   : QBWebConnector.SOAPWebService.instantiateWebService() : AppName: DebuggingService
20170517.16:20:56 UTC   : QBWebConnector.SOAPWebService.instantiateWebService() : AppUniqueName (if available): DebuggingService
20170517.16:20:56 UTC   : QBWebConnector.SOAPWebService.instantiateWebService() : AppURL: http://localhost:3318/Service1.svc
20170517.16:20:56 UTC   : QBWebConnector.SOAPWebService.do_serverVersion() : *** Calling serverVersion().
20170517.16:20:57 UTC   : QBWebConnector.SOAPWebService.do_serverVersion() : Actual error received from web service for serverVersion call: <The message with Action 'http://developer.intuit.com/serverVersion' cannot be processed at the receiver, due to a ContractFilter mismatch at the EndpointDispatcher. This may be because of either a contract mismatch (mismatched Actions between sender and receiver) or a binding/security mismatch between the sender and the receiver.  Check that sender and receiver have the same contract and the same binding (including security requirements, e.g. Message, Transport, None).>. For backward compatibility of all webservers, QBWC will catch all errors under app-not-supporting-serverVersion.
20170517.16:20:57 UTC   : QBWebConnector.SOAPWebService.do_serverVersion() : This application does not contain support for serverVersion. Allowing update operation for backward compatibility.
20170517.16:20:57 UTC   : QBWebConnector.SOAPWebService.do_clientVersion() : *** Calling clientVersion() with following parameter:<productVersion="2.1.0.30">
20170517.16:21:00 UTC   : QBWebConnector.SOAPWebService.do_clientVersion() : Received from clientVersion() following parameter:<clientVersionRet="">
20170517.16:21:00 UTC   : QBWebConnector.SOAPWebService.do_clientVersion() : This application agrees with the current version of QBWebConnector. Allowing update operation.
20170517.16:21:00 UTC   : QBWebConnector.SOAPWebService.do_authenticate() : Authenticating to application 'DebuggingService', username = 'Sysadmin'
20170517.16:21:01 UTC   : QBWebConnector.SOAPWebService.do_authenticate() : *** Calling authenticate() with following parameters:<userName="Sysadmin"><password=<MaskedForSecurity>
20170517.16:21:08 UTC   : QBWebConnector.SOAPWebService.do_authenticate() : QBWC1012: Authentication failed due to following error message.
Index was outside the bounds of the array.
More info:
StackTrace =    at QBWebConnector.WebService.do_authenticate(String& ticket, String& companyFileName)
Source = QBWebConnector
20170517.16:21:08 UTC   : QBWebConnector.RegistryManager.setUpdateLock() : HKEY_CURRENT_USER\Software\Intuit\QBWebConnector\UpdateLock has been set to False
20170517.16:21:08 UTC   : QBWebConnector.RegistryManager.setUpdateLock() : ********************* Update session unlocked *********************
20170517.16:21:08 UTC   : QBWebConnector.WebServiceManager.DoUpdateSelected() : Update completed with errors. See log (QWClog.txt) for details.

@MAS gives the solution at the bottom of the comments but I wanted to call it out in here for those digging for it.

QBWebConnector must connect to a service that ends in asmx. I used end-point routing in .NET Core to define two SOAP end points. One ending with .svc and one ending with .asmx.

QBWebConnector throws the Index was outside the bounds of the array exception if you connect to the .svc but works just fine if you connect to the .asmx.