“HTTP Error 500.19 - Internal Server Error” in IIS 7 / 7.5

I was testing a simple WCF application deployed on my IIS 7.5 machine. This was working fine on my development Windows 7 IIS 7.5 client machine but as soon as I deployed it on my Windows Server 2008 R2 IIS 7.5 machine the application threw the following error:

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

Here’s what we need to keep in mind.

1. Check the error code 0x80070032. You will need Error Code Look-up tool to see what the error code mean. 
   
     ERROR_NOT_SUPPORTED                                           winerror.h
   # The request is not supported. 
   
   
2. Check the Config Error, it says the “The configuration section 'system.serviceModel' cannot be read because it is missing” and it is pointing to the web.config file.

I checked the web.config and found there is an entry for 'system.serviceModel' but I don’t have .net 3.0 installed on my Windows Server 2008 R2 server.

I enabled .net 3.5 from Server Manager –> Features –> Add Features

Things are looking much better now.

Happy troubleshooting.. 
Vivek Kumbhar