Rated 3 out of 5 stars

This is what is happening since yesterday, 9 Jan 2024:
Authorisation Error
Error 400: invalid_request

You can't sign in to this app because it doesn't comply with Google's OAuth 2.0 policy for keeping apps secure.

You can let the app developer know that this app doesn't comply with one or more Google validation rules.

This review is for a previous version of the add-on (0.6.0). 

Thanks for Your comment.

However this isn't the proper place for tickets. Please report to https://github.com/zanonmark/Google-4-TbSync.
Also have a look at https://github.com/zanonmark/Google-4-TbSync/issues/62.

Thanks,
MZ