Existing google calendars don't sync, and I can not add a new google, yahoo or aol calendar
From the iCal Calendars -> Accounts list, after I hit the plus sign to add an account, if I choose Google, Yahoo, or AOL, it gets an 'authentication failed' error, although I have not entered any information. If I choose 'other caldav account' it lets me type in email and password, but will fail with 'unable to verify account name or password'.
Clicking any of the error triangles in the iCal app gives an error I attached here -- "There was an unexpected error with the request (domain DAAccountValidationDomain / error 100)."
By disabling and re-enabling google calendars that previously worked, it loses all context for that calendar but it does not resolve.
I have recently upgraded from Big Sur to Ventura, and it may be that this has never worked since the upgrade. Exchange and iCloud accounts work fine. My iPhone can access all these calendars. The Spark mail app can access these calendars from this system.