Could not load file or assembly System.Web.Http.WebHost after published to Azure web site

Question

I created a web project and it runs well in Visual Studio. However, I got the following error after published it to azure website. What can cause the issue?

Could not load file or assembly 'System.Web.Http.WebHost, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

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.IO.FileLoadException: Could not load file or assembly 'System.Web.Http.WebHost, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

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.

Assembly Load Trace: The following information can be helpful to determine why the assembly 'System.Web.Http.WebHost, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' could not be loaded.

WRN: Assembly binding logging is turned OFF. To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1. Note: There is some performance penalty associated with assembly bind failure logging. To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog].

Following is part of the web.config file.

<system.web>

    <customErrors mode="Off"/>

    <compilation debug="true" targetFramework="4.5" />

    <httpRuntime targetFramework="4.5" />

    <authentication mode="Forms">

      <forms loginUrl="~/Account/Login" timeout="2880" />

    </authentication>

    <pages>

      <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" />

    </handlers></system.webServer>

  <runtime>

    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">

      <dependentAssembly>

        <assemblyIdentity name="DotNetOpenAuth.Core" publicKeyToken="2780ccd10d57b246" />

        <bindingRedirect oldVersion="1.0.0.0-4.0.0.0" newVersion="4.1.0.0" />

      </dependentAssembly>

      <dependentAssembly>

        <assemblyIdentity name="DotNetOpenAuth.AspNet" publicKeyToken="2780ccd10d57b246" />

        <bindingRedirect oldVersion="1.0.0.0-4.0.0.0" newVersion="4.1.0.0" />

      </dependentAssembly>

      <dependentAssembly>

        <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />

        <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" />

      </dependentAssembly>

      <dependentAssembly>

        <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />

        <bindingRedirect oldVersion="1.0.0.0-4.0.0.0" newVersion="4.0.0.0" />

      </dependentAssembly>

      <dependentAssembly>

        <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />

        <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" />

      </dependentAssembly>

      <dependentAssembly>

        <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" />

        <bindingRedirect oldVersion="0.0.0.0-1.5.2.14234" newVersion="1.5.2.14234" />

      </dependentAssembly>

      <dependentAssembly>

        <assemblyIdentity name="EntityFramework" publicKeyToken="b77a5c561934e089" culture="neutral" />

        <bindingRedirect oldVersion="0.0.0.0-5.0.0.0" newVersion="5.0.0.0" />

      </dependentAssembly>

    </assemblyBinding>

  </runtime>

Anyone, please help me, 

Answer 1

Hi Eresh, it seems like the dll is missing in your published or deployed environment is the reason it is working on your local but not in your Azure Website Environment.

Want to learn Azure from scratch! Have a look at this video on Azure provided by Intellipaat:

Now try this, 

Copy Local = true in properties for and assembly(System.Web.Http.WebHost), just redeploy it after this. It will start working.

However, if you receive the similar error - some other assembly missing, then make assembly as copylocal = true, then deploy it again, repeat this process until you are sure of its dependencies.