I have spent two hours experimenting all kinds of remedies, reading posts with similar cases, discussing with a veteran ASP.Net developer. I am still unable to figure out what is wrong.

I have created a bot which is essentially a web app. It works perfectly on the dev machine that runs Windows 10 either using IIS Express or IIS server. Its home page is supposed to show the following:

My_Bot

Describe your bot here and your terms of use etc.

Visit Bot Framework to register your bot. When you register it, remember to set your bot's endpoint to

https://your_bots_hostname/api/messages

However, it shows the following when it is deployed to a Windows Server 2008 R2:

Server Error in '/QnA' Application.

Could not load file or assembly 'System.Web.Helpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

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.FileNotFoundException: Could not load file or assembly 'System.Web.Helpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

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.Helpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' could not be loaded.

Assembly manager loaded from:  C:\Windows\Microsoft.NET\Framework64\v4.0.30319\clr.dll
Running under executable  c:\windows\system32\inetsrv\w3wp.exe
--- A detailed error log follows. 

=== Pre-bind state information ===
LOG: DisplayName = System.Web.Helpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35
 (Fully-specified)
LOG: Appbase = file:///C:/Web Apps/QnA/
LOG: Initial PrivatePath = C:\Web Apps\QnA\bin
Calling assembly : (Unknown).
===
LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\Web Apps\QnA\web.config
LOG: Using host configuration file: C:\Windows\Microsoft.NET\Framework64\v4.0.30319\aspnet.config
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework64\v4.0.30319\config\machine.config.
LOG: Redirect found in application configuration file: 2.0.0.0 redirected to 3.0.0.0.
LOG: Post-policy reference: System.Web.Helpers, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35
LOG: Attempting download of new URL file:///C:/Windows/Microsoft.NET/Framework64/v4.0.30319/Temporary ASP.NET Files/qna/dc0ff7f6/e72280bf/System.Web.Helpers.DLL.
LOG: Attempting download of new URL file:///C:/Windows/Microsoft.NET/Framework64/v4.0.30319/Temporary ASP.NET Files/qna/dc0ff7f6/e72280bf/System.Web.Helpers/System.Web.Helpers.DLL.
LOG: Attempting download of new URL file:///C:/Web Apps/QnA/bin/System.Web.Helpers.DLL.
LOG: Attempting download of new URL file:///C:/Web Apps/QnA/bin/System.Web.Helpers/System.Web.Helpers.DLL.
LOG: Attempting download of new URL file:///C:/Windows/Microsoft.NET/Framework64/v4.0.30319/Temporary ASP.NET Files/qna/dc0ff7f6/e72280bf/System.Web.Helpers.EXE.
LOG: Attempting download of new URL file:///C:/Windows/Microsoft.NET/Framework64/v4.0.30319/Temporary ASP.NET Files/qna/dc0ff7f6/e72280bf/System.Web.Helpers/System.Web.Helpers.EXE.
LOG: Attempting download of new URL file:///C:/Web Apps/QnA/bin/System.Web.Helpers.EXE.
LOG: Attempting download of new URL file:///C:/Web Apps/QnA/bin/System.Web.Helpers/System.Web.Helpers.EXE.

Stack Trace:

[FileNotFoundException: Could not load file or assembly 'System.Web.Helpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.]

[FileNotFoundException: Could not load file or assembly 'System.Web.Helpers, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.]
   System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +0
   System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, RuntimeAssembly reqAssembly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +225
   System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean forIntrospection) +110
   System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +22
   System.Reflection.Assembly.Load(String assemblyString) +34
   System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +48

[ConfigurationErrorsException: Could not load file or assembly 'System.Web.Helpers, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.]
   System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +729
   System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai) +69
   System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig) +226
   System.Web.Compilation.BuildManager.GetPreStartInitMethodsFromReferencedAssemblies() +73
   System.Web.Compilation.BuildManager.CallPreStartInitMethods(String preStartInitListPath, Boolean& isRefAssemblyLoaded) +321
   System.Web.Compilation.BuildManager.ExecutePreAppStart() +170
   System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +734

[HttpException (0x80004005): Could not load file or assembly 'System.Web.Helpers, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +525
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +118
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +708

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.2558.0

Could anyone offer a tip on how to find the remedy?