I\'m setting up a new build server using TFS 2015 and after I configured the agent, when I tried to queue a build I got this error:
No agent could be
Although none of previous answers worked for me, the post by Simon_Weaver pointed me in the right direction.
He mentioned that vstest was in his list, but it wasn't in mine. I fixed it by adding a user-defined capability named "vstest" with the full path to vstest.console.exe under Visual Studio 2017.