Authentication exception when using an NLB solution with Workflow Manager

Problem

When process system processes an order and the workflow manager installation is setup using a NLB solution you might receive this error.

Error: Microsoft.Workflow.Client.AuthenticationException: A response was returned that did not come from the Workflow Manager. Status code = 401

Solution

With Windows Server 2003 SP1 a loopback security check was introduced, and this is what is causing this error.

Check following links for solution.

http://blogs.technet.com/b/sharepoint_foxhole/archive/2010/06/21/disableloopbackcheck-lets-do-it-the-right-way.aspx

http://support.microsoft.com/kb/896861

Troubleshooting guidelines