Bidirectional calendar sync with Google - Unexpected Error signing into Workspace as SuperAdmin

We are using the Teams Calendar Synchronization with Google Workspace, and have had it setup since the summer, June 2025. (see this link for details of functionality https://learn.microsoft.com/en-us/microsoftteams/setup-calendar-syncing-with-google-workspace#set-up-calendar-synchronization) . We have been planning to role this out to users slowly with our initial beta test group was syncronized this past fall and expanded to new users on December 4th 2025. All beta users synchronizations appear to still be working to an extent, with functionality seems being very sporadic. Sometimes an event that is created in Google will sync to Teams in a few mintues, other times it can be several hours. In addition sometimes it will not sync any new events or updates to the Google Calendar, and the only way to get a full sync is if an event is created on the Teams Calendar. So there has been some weird and inconsistent results for us when testing.

On December 4th I expanded our beta test group by successfully synchronizing an additional 22 user accounts. But since mid December(12/15 until now) when I attempt to add more beta users I cannot get logged into my Google Workspace within the Admin App on the Teams Client. When signing into the Calendar Sync feature using my Google SA account it fails to make the connection to Google Workspace. Authentication to google is successful when prompted in the browser and I allow the M365 Mail Migration app successfully. But once it kicks back to the teams client it spins for a minute or two and then fails with "Unexpected Error: Please sign into your Google Workspace admin account" error being displayed. If I try to sign in again, I get the same result over and over. Keep in mind this was not the case previously, as I was able to sync additional beta users on 12/4.

When viewing the article above, it states "New customer onboarding for calendar syncing between Google Workspace and Microsoft Teams is currently paused. Existing customers with sync set up can continue using the feature without interruption." I would think that since we have had this setup since June 2025, and our inital beta test group are still working to an extent, that this suspension of onboarding clients would not affect us.  I wonder if the fact that I have had to Allow the M365 Mail Migration app every time I have ever setup a user to syncronized, makes me wonder if this is impacting us.

The functionality is so sporadic and now that I cannot even get logged in successfully, I am not holding my breath that this will ever work.

Our organization has been looking forward to using this functionality since information was published on the Roadmap almost two years ago, and I don't want to go to executive management and tell them we have to scrap the idea. That will just make my users hate Teams even more, and all the effort put in to configure our environment will be moot as users will shy away from using the tools we are trying to provide, and just use something else.

Has anyone else experienced this issue?