HTTP Status 400 With Reporting Services

May 2007 - There are probably a myriad of reasons to get the error "The request failed with HTTP status 400: Bad Request" in Reporting Services running with TFS, but here is why we got the error.

While trying to get our TFS instance behind a fully qualities DNS name we added tfs.int.mycompany.com to host header entry on the Default Web Site on our TFS App Tier. After adding this entry users could still see Reports in Visual Studio, but when Right Clicking and selecting Show Report Site Internet Explorer would pop up and give us the error ""The request failed with HTTP status 400: Bad Request". As a side note, adding this entry in the host header did nothing for us while trying to get our App Tier behind DNS.

Once we removed that value, the error went away. Hope this helps anyone else.