Server error - Attempted to divide by zero

I am getting the below error in my code during login itself. Looks like code is unable to access DB. I checked everything and it looks fine. I have added the snapshot of error. I got this error in console:

Failed to load resource: the server responded with a status of 500 (Internal Server Error) 50224/api/UserDetails 

when clicked on 50224/api/UserDetails i got error which is attached as image in this question. Any help? Thanks in advance..

My GlobalAsax file:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Http;
using System.Web.Mvc;
using System.Web.Optimization;
using System.Web.Routing;
using System.Web.Http.Cors;
namespace OCB.WebAPI
{
    public class WebApiApplication : System.Web.HttpApplication
    {
        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();
            WebApiConfig.Register(GlobalConfiguration.Configuration);
            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            BundleConfig.RegisterBundles(BundleTable.Bundles);

            GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
            GlobalConfiguration.Configuration.Formatters.Remove(GlobalConfiguration.Configuration.Formatters.XmlFormatter);
            GlobalConfiguration.Configure(WebApiConfig.Register);

            GlobalConfiguration.Configuration.EnsureInitialized();


}

        public void Application_BeginRequest(object sender, EventArgs e)
        {
            HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", "*");
            if (HttpContext.Current.Request.HttpMethod == "OPTIONS")
            {
                HttpContext.Current.Response.AddHeader("Cache-Control", "no-cache");
                HttpContext.Current.Response.AddHeader("Access-Control-Allow-Methods", "GET, POST");
                HttpContext.Current.Response.AddHeader("Access-Control-Allow-Headers", "Content-Type, Accept");
                HttpContext.Current.Response.AddHeader("Access-Control-Max-Age", "1728000");
                HttpContext.Current.Response.End();
            }


        }
    }
}

Stack trace:

[DivideByZeroException: Attempted to divide by zero.]
   System.Decimal.FCallDivide(Decimal& d1, Decimal& d2) +0
   System.Web.Http.Routing.RoutePrecedence.Compute(HttpParsedRoute parsedRoute, IDictionary`2 constraints) +242
   System.Web.Http.Routing.DirectRouteFactoryContext.CreateBuilder(String template, IInlineConstraintResolver constraintResolver) +183
   System.Web.Http.Routing.DirectRouteFactoryContext.CreateBuilderInternal(String template) +8
   System.Web.Http.RouteAttribute.System.Web.Http.Routing.IDirectRouteFactory.CreateRoute(DirectRouteFactoryContext context) +21
   System.Web.Http.Routing.DefaultDirectRouteProvider.CreateRouteEntry(String prefix, IDirectRouteFactory factory, IReadOnlyCollection`1 actions, IInlineConstraintResolver constraintResolver, Boolean targetIsAction) +52
   System.Web.Http.Routing.DefaultDirectRouteProvider.CreateRouteEntries(String prefix, IReadOnlyCollection`1 factories, IReadOnlyCollection`1 actions, IInlineConstraintResolver constraintResolver, Boolean targetIsAction) +113
   System.Web.Http.Routing.DefaultDirectRouteProvider.GetActionDirectRoutes(HttpActionDescriptor actionDescriptor, IReadOnlyList`1 factories, IInlineConstraintResolver constraintResolver) +64
   System.Web.Http.Routing.DefaultDirectRouteProvider.GetDirectRoutes(HttpControllerDescriptor controllerDescriptor, IReadOnlyList`1 actionDescriptors, IInlineConstraintResolver constraintResolver) +187
   System.Web.Http.Routing.AttributeRoutingMapper.AddRouteEntries(SubRouteCollection collector, HttpConfiguration configuration, IInlineConstraintResolver constraintResolver, IDirectRouteProvider directRouteProvider) +241
   System.Web.Http.Routing.<>c__DisplayClass4.<MapAttributeRoutes>b__1() +57
   System.Web.Http.Routing.RouteCollectionRoute.EnsureInitialized(Func`1 initializer) +52
   System.Web.Http.Routing.<>c__DisplayClass2.<MapAttributeRoutes>b__0(HttpConfiguration config) +91
   System.Web.Http.HttpConfiguration.EnsureInitialized() +23
   OCB.WebAPI.WebApiApplication.Application_Start() in c:\Projects\OCB_Lab\.OCB.WebAPI\Global.asax.cs:26

[HttpException (0x80004005): Attempted to divide by zero.]
   System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode(HttpContext context, HttpApplication app) +10062117
   System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext, HttpContext context, MethodInfo[] handlers) +118
   System.Web.HttpApplication.InitSpecial(HttpApplicationState state, MethodInfo[] handlers, IntPtr appContext, HttpContext context) +173
   System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +336
   System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +296

[HttpException (0x80004005): Attempted to divide by zero.]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +10043408
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +95
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +254

Error Image added here