Civil 3D Extension Connection Issue

We have a user who cannot seem to connect to the project manager interface through the Civil 3D extension. He has access to the OpenGround ribbon within Civil 3D. When "Connect' is clicked, an authenticating window appears for a brief moment and then disappears. He has all the same updates as I do and yet I have no issues. We have tried the BlueBeam uninstall/reinstall approach with no luck. We also elevated him to an Openground Adminstrator to see if that did anything, but no change. I do recall that I used to be able to give users access rights to the various OpenGround applications through the old Admin Portal, but that is no longer an option, so I don't know how to check that. We are still running on the older licensing system that uses floating cloud licenses (not the Virtuoso licenses). Should we try uninstalling/reinstalling Civil 3D?