Dynamics AX 2012 Help Server: Connection-Error just ...

Today I faced a problem that took me more than two hours to solve.

I had to install a Dynamics AX 2012 Development-Environment with two independent Servers. Both are Windows Server 2008 R2. One hosts a SQL Server 2008 R2 with Report Services and Analysis Services. The other one hosts the AOS and the Dynamics AX 2012 Help Server.

“Help Server” is a new feature of Dynamics AX 2012. It hosts the default help system of Dynamics AX 2012 as well as it gives you the possibility to add your own documentation. Of course this was also possible with Dynamics AX 2009. But according to Microsoft the new Help Server should be simpler.
We will see. But after today’s installation problems I have my doubts.

Back to the problem and to the hard- and software we use.
Both Servers were maiden-like. Meaning: The one hosting the AOS had just a Standard-Installation of Windows Server R2 with all Patches and Service Packs when starting installation. The second one hosting the Database and Reporting & Analysis Services had an additional installation of SQL Server 2008 R2 with SP1. “Help Server” needs IIS running. So IIS was installed on the first server

Long story short: After a more or less problem-free installation I’ve added the users as the last step of my installation-duties. Fewer problems than expected – just a prefect day. That was what I thought.
Then I checked Help Server… and got an error-message that AX 2012 was unable to connect to Help Server Website.
After checking the URL direct in an Internet-Browser I got the following error-message:

Could not load type 'System.ServiceModel.Activation.HttpModule' from assembly 'System.ServiceModel, Version=3.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.
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.TypeLoadException: Could not load type 'System.ServiceModel.Activation.HttpModule' from assembly 'System.ServiceModel, Version=3.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.

A quick, first Google-search showed that this is a common error-message linked to .NET.
Different token-numbers point to different problems. After more than one hour of searching I realised that the day was not that perfect I first thought. Then I found a helpful forum-post which finally led me to the following Microsoft Support-Page: http://support.microsoft.com/kb/2015129

The cause of the problem in short words:
This issue occurs because the Applicationhost.config file for Windows Process Activation Service (WAS) has a section defined that is incompatible with the .NET Framework 4.0.

The resolution:
Run the following command in command shell:
aspnet_regiis.exe /iru

The Aspnet_regiis.exe file can be found in one of the following locations:
(32-bit OS): %windir%\Microsoft.NET\Framework\v4.0.30319
(64-bit OS): %windir%\Microsoft.NET\Framework64\v4.0.30319

Just try the solution provided in this article maybe it helps you, too.

To additional tips:
1. Execute command shell as Administrator.
2. Restart IIS with the command IISReset