Have you confirmed that you're still signed in to the Google account on the Mac? Not in your eMail app, but in the Internet Accounts Preference Pane?
Looks like it's a backend issue with Google servers. I'm impacted as well, as are many others.
https://support.google.com/calendar/thread/12612472?hl=en
Looks like it's a backend issue with Google servers. I'm impacted as well, as are many others.
https://support.google.com/calendar/thread/12612472?hl=en