title: How to see what caused "A task was cancelled" error?
body: <p>I have an ASP.NET MVC 5 application that is running on Azure and over the past few months on a couple of occasions the site has frozen and I can't see any services that are down and the only thing I can see error log wise is the following which doesn't really help.  I have been able to restart the site and it has worked just fine but I need to see what is going wrong.  When I do get the error below I get hundreds of them at the same time.</p>
  
  <pre><code>System.Threading.Tasks.TaskCanceledException: A task was canceled.
     at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
     at System.Web.Http.Controllers.ApiControllerActionInvoker.&lt;InvokeActionAsyncCore&gt;d__0.MoveNext()
  --- End of stack trace from previous location where exception was thrown ---
     at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
     at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
     at System.Web.Http.Controllers.ActionFilterResult.&lt;ExecuteAsync&gt;d__2.MoveNext()
  --- End of stack trace from previous location where exception was thrown ---
     at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
     at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
     at System.Web.Http.Controllers.ExceptionFilterResult.&lt;ExecuteAsync&gt;d__0.MoveNext()
  </code></pre>