Get calendar events from gmail into Apple Calendar

My Apple calendar on MacBookPro is not showing events from one particular gmail account, but they show up in my iphone. So it works at the gmail end, but my Mac settings are wrong.

In my Mac calendar, in the Calendar list, there is a triangle adjacent the gmail address. Clicking this gives the following message: "Your calendar couldn't be refreshed. Access to account xxx.gmail.com is not permitted."

In (MacBook) Calendar>Settings> Accounts the gmail account is enabled. The calendar lists in both devices look similar.

Software is Tahoe 26.5.1 and iOS 26.5.

Please advise.