title: Debugging, Source Not Found, AsyncExtensions.cs not found
body: <p>I am trying to debug a webjob on azure and I get the following error: Source Not Found, AsyncExtensions.cs not found.</p>
  
  <p>I am working on VS 2015 and the webjob is part of an ASP.NET MVC solution deployed on Azure.</p>
  
  <p>I had published the webjob by right-clicking on it and doing Publish as Azure webjob and selecting Debug configuration.
  I started debug by right-click on the webjob and selecting Debug, Start New Instance.
  When the execution reaches a problematic line, I get the error above instead of the error corresponding to the problematic line. This has happened on several different webjobs.</p>