OpsHub OH-TFS-Connector-0048: Failed to login to T

I'm running a TFS -> VSTS migration using OpsHub Visual Studio Online Migration utility.

Version-1.0

OpsHub Integration Manager Framework-OVSMU-V2.0.0.002

I keep getting errors similar to the following:

OH-ConnLoader-0003: Connector for system name : tfs.XXXX.com\XXX to XXXX.visualstudio.com _PROJECT| TFS Target 1456778794042 Source TFS 1456778794043 could not be instantiated due to OH-TFS-Connector-0060: Unable to initialize TFS SCM Connector. OH-TFS-Connector-0048: Failed to login to Team Foundation Server : https://xxxx.visualstudio.com/ with user : null. Server Error : TF400324: Team Foundation services are not available from server https://tfsprodscussu5.app.visualstudio.com/A74e933d7-11c5-493b-af7e-a9e81b64ff78. Technical information (for administrator): Page not found.. You may have given wrong credentials or credentials are not valid now.

I don't get the errors repeatedly, but about once a day. Since I'm the only one executing the migration and I can't watch it all day and night when we have these failures overnight I lose hours of potential migration time. When the migration utility hits this error it halts the migration until you start it over. So far I've been running for 3 days and have only been able to migrate 3000 code items. At this pace it will take me 11 days to migrate this one project, just the code items!

Is there any work around for this error? Why does the migration halt when it hits this error.

Try clearing the Team Foundation cache on your migration computer. To do so, follow these instructions:

Close OpsHub and any other .NET applications you might have running.
Delete any files that might be in these folders:
- %localappdata%\Microsoft\Team Foundation\3.0\Cache
- %localappdata%\Microsoft\Team Foundation\4.0\Cache
- %localappdata%\Microsoft\Team Foundation\5.0\Cache
- %localappdata%\Microsoft\Team Foundation\6.0\Cache
Open OpsHub and resume your migration.

We had the same issue earlier today, which completely blocked our migration for 3 hours until I did this.

If this is happening to you daily, then you might want to do this each afternoon (until your migration is complete).