Authentication fails using Legacy Odata import wizard

Up until recently, I have always been able to establish connections to an on-premise Project Server database using either the legacy Odata import wizard or the new Odata import wizard.  As of last month, I can no longer establish a connection using the legacy Odata import wizard or refresh reports that were built using legacy Odata import wizard, however I can still successfully query or refresh reports using the new Odata import wizard.  

The error message that I have started to get when using the legacy Odata import wizard is "The underlying connection was closed: An unexpected error occurred on a send.  Authentication failed because the remote party has closed the transport stream."

Any assistance on why this may have started happening would be greatly appreciated.