How to deal with this error 'Maximum request length exceeded' in aspx Web Forms?

My Home Page has some menu buttons on the top such as: Home, Promotion, View Products, About Us and Contact Us.

When I run the Home Page, it is running perfectly and then I click on the Promotion button, it works and when I click on Contact Us, it is showing error "Maximum request length exceeded". This was just one scenario though. Another scenario was I again run the Home page and then I click on View Products button and then I try to come back to Home page, it is showing the same error message. In other words, there are few other random scenarios leading to the same error message.

In the web page, this is the error message with details being displayed:

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.Web.HttpException: Maximum request length exceeded.

Source Error: 

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. 

Stack Trace: 

[HttpException (0x80004005): Maximum request length exceeded.]
   System.Web.HttpRequest.GetEntireRawContent() +9935948
   System.Web.HttpRequest.FillInFormCollection() +415
   System.Web.HttpRequest.EnsureForm() +69
   System.Web.HttpRequest.get_Form() +13
   System.Web.HttpRequestWrapper.get_Form() +14
   System.Web.UI.PageRequestManager.IsAsyncPostBackRequest(HttpRequestBase request) +225
   System.Web.Handlers.ScriptModule.HttpResponse_Redirecting(Object sender, EventArgs e) +83
   System.Web.HttpResponse.Redirect(String url, Boolean endResponse, Boolean permanent) +411
   System.Web.HttpResponseWrapper.RedirectPermanent(String url) +18
   Microsoft.AspNet.FriendlyUrls.FriendlyUrlsModule.RedirectToFriendlyUrl(HttpContextBase httpContext, IFriendlyUrlRoute route, IVirtualPathUtility virtualPathUtility) +305
   Microsoft.AspNet.FriendlyUrls.FriendlyUrlsModule.<Init>b__0(Object sender, EventArgs e) +171
   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +141
   System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +48
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +71 

And this is my web.config file:

<?xml version="1.0" encoding="utf-8"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
  <configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
  <connectionStrings>
    <add name="DefaultConnection" connectionString="Data source=LAPTOP-ODS96MIK\\MSSQL2014; database = Grocery_Demo; integrated security=SSPI"
      providerName="System.Data.SqlClient" />
    <add name="Grocery_DemoConnectionString" connectionString="Data Source=LAPTOP-ODS96MIK\MSSQL2014;Initial Catalog=Grocery_Demo;Integrated Security=True"
      providerName="System.Data.SqlClient" />
  </connectionStrings>
  <system.web>
    <authentication mode="None" />
    <compilation debug="true" targetFramework="4.5.2" />
    <httpRuntime targetFramework="4.5.2" />
    <pages>
      <namespaces>
        <add namespace="System.Web.Optimization" />
        <add namespace="Microsoft.AspNet.Identity" />
      </namespaces>
      <controls>
        <add assembly="Microsoft.AspNet.Web.Optimization.WebForms" namespace="Microsoft.AspNet.Web.Optimization.WebForms" tagPrefix="webopt" />
      </controls>
    </pages>
    <membership>
      <providers>
        <!--
          ASP.NET Membership is disabled in this template. Please visit the following link http://go.microsoft.com/fwlink/?LinkId=301889 to learn about the ASP.NET Membership support in this template
        -->
        <clear />
      </providers>
    </membership>
    <profile>
      <providers>
        <!--
          ASP.NET Membership Profile is disabled in this template. Please visit the following link http://go.microsoft.com/fwlink/?LinkId=301889 to learn about the ASP.NET Membership support in this template
        -->
        <clear />
      </providers>
    </profile>
    <roleManager>
      <!--
            ASP.NET Membership Role is disabled in this template. Please visit the following link http://go.microsoft.com/fwlink/?LinkId=301889 to learn about the ASP.NET Membership support in this template
        -->
      <providers>
        <clear />
      </providers>
    </roleManager>
    <!--
            If you are deploying to a cloud environment that has multiple web server instances,
            you should change session state mode from "InProc" to "Custom". In addition,
            change the connection string named "DefaultConnection" to connect to an instance
            of SQL Server (including SQL Azure and SQL  Compact) instead of to SQL Server Express.
      -->
    <sessionState mode="InProc" customProvider="DefaultSessionProvider">
      <providers>
        <add name="DefaultSessionProvider" type="System.Web.Providers.DefaultSessionStateProvider, System.Web.Providers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" />
      </providers>
    </sessionState>
  </system.web>
  <system.webServer>
    <modules>
      <remove name="FormsAuthentication" />
    </modules>
  </system.webServer>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Newtonsoft.Json" culture="neutral" publicKeyToken="30ad4fe6b2a6aeed" />
        <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="WebGrease" culture="neutral" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-1.5.2.14234" newVersion="1.5.2.14234" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="EntityFramework" publicKeyToken="b77a5c561934e089" />
        <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Owin" culture="neutral" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-3.0.1.0" newVersion="3.0.1.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Owin.Security.OAuth" culture="neutral" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-3.0.1.0" newVersion="3.0.1.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Owin.Security.Cookies" culture="neutral" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-3.0.1.0" newVersion="3.0.1.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Owin.Security" culture="neutral" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-3.0.1.0" newVersion="3.0.1.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="mssqllocaldb" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
  </entityFramework>
  <system.codedom>
    <compilers>
      <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:6 /nowarn:1659;1699;1701" />
      <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:14 /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+" />
    </compilers>
  </system.codedom>
</configuration>

I'm not sure if I need to change anything in web.config file.

Even if a change is required in the web.config file then it would be helpful if the recommended solution is provided.