After changing my xbox gamertag, I became unable to get back in NGS. It throws the following error

Disconnected due to an authentication error Please wait a while and try again, or send an error report through our inquiry form [No. 787]

I was able to play NGS when the beta started, so I can only correlate this sudden issue with the gamertag change.

This issue does not happen in PSO2, I'm still able to access it via the MS store and Steam even after the gamertag change