title: Why is my OpsHub migration periodically failing part way through for the included error?
body: <p>I have been having constant issues with the OpsHub Migration Utility erroring at different stages in setting up a migration, but when I finally get a migration going it fails after 15 minutes or so with the following error:</p>
  
  <blockquote>
    <p>"Unable to get prject map for system : {my on-premise TFS url} to {my VSTS url}| TFS Source 1462312056714 Source TFS 1462312056719 due to : </p>
    
    <p>OpsHub-014301: Error in getting project metadata for system : </p>
    
    <p>TFS.OH-TFS-Connector-0048: Failed to login to Team Foundation Server : {my on-premise TFS url} with user : null. </p>
    
    <p>Server Error : TF400324: Team Foundation services are not available from server {my on-premise TFS url}.
    Technical information (for administrator):
    The underlying connection was closed: An unexpected error occurred on a receive.. You may have given wrong credentials or are not valid now..."</p>
  </blockquote>
  
  <p>I previously tried doing migration with ~6500 Changesets (our main project) and got a similar error after an hour, except that none of the changesets had passed. So, I tried migrating a smaller Team project with 182 changesets and it failed after 72 changesets. </p>
  
  <p><a href="https://i.stack.imgur.com/bSLVW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/bSLVW.png" alt="Failure at 72"></a></p>
  
  <p>This smaller migration then restarted on its own and was able to get to 148/189 changesets before failing again for the same error.</p>
  
  <p><a href="https://i.stack.imgur.com/hqQVl.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/hqQVl.png" alt="Failure at 148"></a></p>
  
  <p>Eventually I was able to complete all 189 changesets, but it took a long time to do so (2 hours). I can't even begin to hope that a migration of 6500 will complete in a reasonable amount of time. It seems I shouldn't be having credential issues after starting a migration so why is this error happening intermittently? Why is the user null?</p>
  
  <p>I will add that prior to starting the smaller migration, I did clear the following:</p>
  
  <blockquote>
    <p>1)%localappdata%\Microsoft\Team Foundation\3.0\Cache</p>
    
    <p>2)%localappdata%\Microsoft\Team Foundation\4.0\Cache </p>
    
    <p>3)%localappdata%\Microsoft\Team Foundation\5.0\Cache</p>
  </blockquote>