Fixed the issue: Some tests failed in TFS 2013 build due to the Error Code: 502 Proxy Error: The ISA Server denied the specified Uniform Resource Locator

We just upgraded from TFS 2010 to TFS 2013, but we still use the same Build Agent. One interesting part was that after I pushed a new build, some tests failed in TFS build and here was the error message.

Error Code: 502 Proxy Error: The ISA Server denied the specified Uniform Resource Locator

I was not aware of this IP address and this server. After I logged to the Build Agent and used mstest to run one test again, the test still failed. After looking into this issue for a while, here are the steps to fix the build issue.

Open IE and go to Tools > Internet Options > Connections > LAN Settings > Proxy Server > Advanced > Exceptions 

Add IP address and domain name (i.e 10.2.1.5; xxx.domain.com) and apply the changes.

Run the test again or queue a new build. The tests pass in TFS 2013 build.