This message keeps appearing for both my gmail accounts on my Z30.
I have tried logging out and back in. Still the same.
I have tried deleting the gmail accounts from the phone and recreating them, but this msg keeps reoccurring.
AFAIK, it does not affect the email, I am still receiving it on my phone, without issue.
Just wondering if I can get rid of this annoyance?
If you don't need the Google Calendar account on your device, go to settings, accounts, tap on the Gmail account and remove only the calendar account. If you don't use Google contacts either you can remove that one as well - although you probably should have your contacts syncing with the cloud somehow in 2020.