When multiple versions of the .NET Framework are executing side-by-side on a single computer, the ASP.NET ISAPI version mapped to an ASP.NET application determines which version of the common language runtime (CLR) is used for the application.
Above command will Installs the version of ASP.NET that is associated with Aspnet_regiis.exe and only registers ASP.NET in IIS.
Hello Thanks for the question;
To resolve: "Could not load type 'System.ServiceModel.Activation.HttpModule' from assembly 'System.ServiceModel, Version=3.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'"
In Windows Features check all for .NET 4 Advanced Services & .NET 3.5
Just like Nicolas Gago I tried aspnet_regiis.exe -iru but it didn't work. After the features were on then it yellow screen error was gone. Thanks;
From the Server Manager's Features node, you can also remove some of the sub-items under the .NET Framework 3.5.1 Features that are installed by the activation of some of the other roles.
For instance, removed the WCF Activation Features as follows and our websites came back:
I got this error after I accidentally published one website into the directory of another website. The two websites had different versions of .net. What fixed it for me was changing the application pool. To do that, in the IIS manager:
click the website => Advanced Settings... (on the right) => click to the right of Application Pool => a button with "..." should appear => select ".NET v4.5 Classic"
If that application pool doesn't work, try some of the others.
We are using a web service along side a web site and when we publish the web site it returns same this error. We found out that by going into IIS and removing the ServiceModel from Modules and the svc-Integrated from the Handler Mappings the error went away.
I am late, hope it will help someone ....This is a known issue with IIS 8.0
The solution is to delete the 3.x module and handler from IIS manager. You could delete them at the application or site level if you want to keep them in applicationHost.config. But I wanted to delete them from applicationHost.config. do the following steps:
In IIS manager, click the machine name node.
In “Features View”, double-click “Modules”.
Find “ServiceModel” and remove it.
Image 1 for Solve IIS 8 Error: Could not load type ‘System.ServiceModel.Activation.HttpModule’
Go back to the machine name node’s “Features View”, double-click “Handler Mappings”.
Find “svc-Integrated” and remove it.
Image 2 for Solve IIS 8 Error: Could not load type ‘System.ServiceModel.Activation.HttpModule’
You might changed the IIS features settings.The easy steps to resolve by open command prompt with run as administrator(For Windows Server 2008) and run the command
C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis.exe -iru
this will set up ASP.Net 4.0 ,Then Reset the IIS by the command
iisreset
This issue occurs because the Applicationhost.config file for Windows Process Activation Service (WAS) has some tags that are not compatible with the .NET Framework 4.0.
Based on your environment, you have 4 workarounds to solve this issue: