MVC 4 website load shows HTTP Error 500.19

Question

I created a new ASP.NET MVC 4 application based on Internet application template, I could succesfully run it and authenticate user from within VS 2012 Express.

Then published it to a folder in wwwroot, then in IIS 7.5 manager created a virtual directory pointing to that folder, and converted it to an application using a separate 4.0 integrated pool.

When I tried to browse the application from within the IIS manager I get the next error:

HTTP Error 500.19 - Internal Server Error, The requested page cannot be accessed because the related configuration data for the page is invalid.

Config Error: Cannot add duplicate collection entry of type 'add' with unique key attribute 'name' set to 'ExtensionlessUrlHandler-Integrated-4.0'

Config source:

56:       <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0"/>
57:       <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" resourceType="Unspecified" requireAccess="Script" preCondition="integratedMode,runtimeVersionv4.0" />   
58:     </handlers>

searched here,I found the corresponding answer:

Resolution 1

Delete the malformed XML element from the ApplicationHost.config file or from the Web.config file.

My web.config file is as below:

    <?xml version="1.0"?>
    <configuration>
      <configSections>
        <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false"/>
      </configSections>
      <connectionStrings>
        <add name="DefaultConnection" connectionString="Data Source=(LocalDb)\v11.0;Initial Catalog=aspnet-digixMVC4-20120915233326;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\aspnet-digixMVC4-20120915233326.mdf" providerName="System.Data.SqlClient"/>
      </connectionStrings>
      <appSettings>
        <add key="webpages:Version" value="2.0.0.0"/>
        <add key="webpages:Enabled" value="false"/>
        <add key="PreserveLoginUrl" value="true"/>
        <add key="ClientValidationEnabled" value="true"/>
        <add key="UnobtrusiveJavaScriptEnabled" value="true"/>
      </appSettings>

      <!--
        The following attributes can be set on the <httpRuntime> tag.
          <system.Web>
            <httpRuntime targetFramework="4.5"/>
          </system.Web>
      -->
      <system.web>
        <compilation targetFramework="4.5"/>
        <httpRuntime/>
        <authentication mode="Forms">
          <forms loginUrl="~/Account/Login" timeout="2880"/>
        </authentication>
        <pages controlRenderingCompatibilityVersion="4.0">
          <namespaces>
            <add namespace="System.Web.Helpers"/>
            <add namespace="System.Web.Mvc"/>
            <add namespace="System.Web.Mvc.Ajax"/>
            <add namespace="System.Web.Mvc.Html"/>
            <add namespace="System.Web.Optimization"/>
            <add namespace="System.Web.Routing"/>
            <add namespace="System.Web.WebPages"/>
          </namespaces>
        </pages>
      </system.web>
      <system.webServer>
        <validation validateIntegratedModeConfiguration="false"/>
        <handlers>
          <remove name="ExtensionlessUrlHandler-ISAPI-4.0_32bit"/>
          <remove name="ExtensionlessUrlHandler-ISAPI-4.0_64bit"/>
          <remove name="ExtensionlessUrlHandler-Integrated-4.0"/>
          <add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0"/>
          <add name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0"/>
<add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0"/>
          <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" resourceType="Unspecified" requireAccess="Script" preCondition="integratedMode,runtimeVersionv4.0" />      
        </handlers>
      </system.webServer>
      <runtime>
        <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
          <dependentAssembly>
            <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364g85"/>
            <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0"/>
          </dependentAssembly>
          <dependentAssembly>
            <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364g85"/>
            <bindingRedirect oldVersion="1.0.0.0-4.0.0.0" newVersion="4.0.0.0"/>
          </dependentAssembly>
          <dependentAssembly>
            <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364g85"/>
            <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0"/>
          </dependentAssembly>
        </assemblyBinding>
      </runtime>
      <entityFramework>
        <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework"/>
      </entityFramework>
    </configuration>

As I am a poorly skilled developer in MVC 4, I would ask if someone could find out the malformed xml element in the file above.

Answer 1

This is true for ASP.NET WebAPI 5.2 too..

I had

  <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
  <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />

Which I changed to

  <add name="ExtensionlessUrlHandler-Integrated-4.0a" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
  <add name="ExtensionlessUrlHandler-Integrated-4.0b" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />

Thats it.. It worked.