title: How to debug iis "Service Unavailable" and (possibly) related w3wp.exe error in event viewer
body: <p>suddently my website (asp.net-mvc  iis) is down with error "Service unavailable".  when i go to check the event viewer i see this error:</p>
  
  <p><strong>Source</strong>: VsJitDebugger</p>
  
  <p><strong>Error:</strong> An unhandled exception ('') occurred in w3wp.exe [5208]. Just-In-Time debugging this exception failed with the following error: Debugger could not be started because no user is logged on.</p>
  
  <p>i tried starting and stopping the service but didn't seem to fix anything.</p>
  
  <p>Is this an application bug or an enviroment issue? Can someone point me in  the right direction on how to debug this.  Site works fine locally (of course)</p>