Google Calendar error message from Mail

I keep getting this message in Mail when trying to combine my wife's gmail account to Mac calendar:

The server responded with an error
https://calendar.google.com/calendar/dev/[email protected]/user/ is not a location that supports this request.

My wife's calendar entries do show up on my iCal. Does anyone know why I get this message.

Thanks....

I also have that problem

I'm looking for a solution to this problem. I keep getting alerts and don't know how to fix the problem! Anyone??

I stil occasionally get the message, but bot consistently. It apparently doesn't affect the calendar events.

How have you set up Google Calendar? Do you happen to have two step authentication enabled?

I just started getting this message, too

I just started getting this same error message yesterday after I removed an old account. The account I removed was not a Google account. Maybe the timing of the error message is just a coincidence. I thought maybe it would go away after restarting my computer, but I'm still getting it today.