Hey Nodger,
Thanks for posting your question in Apple Support Communities.
If you are having issues with your Google Account in the Calendar app, try removing it and adding it back.
On a Mac you can do this by going to System Preferences > Internet Accounts > Remove the affected account > Select Add Account > Google > Sign in.
If you are on an iPhone or iOS/iPadOS device, go to Settings > Calendar > Accounts > Affected Account > Remove Account.
You can also find some helpful info in this article: If your iCloud Contacts, Calendars, or Reminders won’t sync. It mentions iCloud contacts, but there should still be some steps relevant to your issue as well.
Best Wishes.