A quick update - I closed the calendar reminder window, and the Error Console threw a message about the timezone offset. Thunderbird was configured to use the system timezone, which I then changed to manual using the right timezone. Error Console is no longer showing the timezone error, but it continues to show the shared properties error.

I take that back. I'm still having Thunderbird timezone problems no matter whether I set Thunderbird to use the system timezone or I set it manually in Thunderbird.

I'm harping on this because I saw earlier a message somewhere that somebody solved a problem with being unable to dismiss reminders by adjusting their timezone.

So, in the hope that it will help somebody help me, here are the details:

Win 11, Set time automatically = on, Adjust for daylight saving time automatically = on, Time zone = (UTC-05:00) Eastern Time (US & Canada).

Thunderbird Settings/Calendar: Use system timezone is selected (although, the greyed-out timezone pick box where I would select one if I'd chosen "set timezone manually" has America/Toronto greyed out - if I were indeed picking manually, that's the one I'd pick being in Canada and in the same timezone as Toronto).

I restart Thunderbird, start up Error Console, and I get my 70-ish reminders come up. I try to dismiss all, and I get the "shared properties can only be changed" errors, plus, much to my surprise:

[calGoogleCalendar] 2023-07-05T20:25:00-04:00 does not match timezone offset for America/Toronto

I'm not sure why it's giving me that; why would it want to compare anything to America/Toronto, when I've told it to use the system timezone?

Sorry to expand the problem set, but I'm starting to suspect all these things are related somehow. I don't seem to be able to process some incoming calendar event messages; limited testing so far suggests the problem may be restricted to event cancellations when I'm not the originator, AND when the original invite had changes made to it. That is to say, I seem to be able to accept and process a straightforward cancellation. I can accept events, single or recurring, but when a complicated cancellation comes in I seem to get an 80004005.

Really no idea where to go from here, but maybe an obvious step is to think about removing the complication of Provider. At one point I thought I'd read that native TB didn't allow write access to Google calendars; has this changed with the most recent version? If so, easy enough to unsubscribe the calendar, remove Provider, try to re-establish the calendar (I'd have to figure out how to do that).

Does any of this ring any bells with anyone? Is there any additional information I could provide to help you help me?

Hi,

Since upgrading to v115 I am also unable to dismiss calendar reminders for an appointment in my calendar - I am not the organiser, so it tallies with the OP's experience.

Steven

From the Error Console:

Calendar: [calGoogleCalendar] Modifying item Financial Advice failed:2147500037: {

"error": {
 "errors": [
  {
   "domain": "calendar",
   "reason": "forbiddenForNonOrganizer",
   "message": "Shared properties can only be changed by the organizer of the event."
  }
 ],
 "code": 403,
 "message": "Shared properties can only be changed by the organizer of the event."
}

}

I am merely trying to dismiss the remind, not alter the event!

From the Error Console:

Calendar: [calGoogleCalendar] Modifying item Financial Advice failed:2147500037: {

"error": {
 "errors": [
  {
   "domain": "calendar",
   "reason": "forbiddenForNonOrganizer",
   "message": "Shared properties can only be changed by the organizer of the event."
  }
 ],
 "code": 403,
 "message": "Shared properties can only be changed by the organizer of the event."
}

}

I am merely trying to dismiss the reminder, not alter the event!

So I solved my problem, and am describing the fix here in case anyone else has the same problem and stumbles upon this post. I upgraded to the latest version of Thunderbird, unsubscribed my Google calendar, deleted the Provider add-on. Closed and re-started Thunderbird, and added my Google calendar with native Thunderbird. Everything works as expected.