BCart505 I get hit by the null auth token many times per day too, sent back to EXO Admin Center home page. I think it might be related to Continuous Access Evaluation and Exchange team going the full distance with supporting that feature. Continuous access evaluation in Microsoft Entra - Microsoft Entra ID | Microsoft Learn.
I use Privileged Identity Management each day to activate my assigned roles, and when I use EXO PowerShell, any changes in my activated roles will cause me to have to redo Connect-ExchangeOnline in order to regain functionality. I think this might be the exact same thing (CAE), just being experienced in PowerShell that way, vs how it plays out in EXO Admin Center. In the admin center, I think you get sent back to home even when there've been no role activation changes.
All that said, I don't see any mention of PIM or role activation/deactivation in the CAE documentation. So this is a guess for now. It would be nice if we could get sent back to wherever we were already at in the EXO Admin Center.