Server responded with “501” to operation CalDAVUpdateShareesQueuableOperation

[christiaan]

Does anybody know why I might be getting the following message in Calendar for macOS for a calendar syncing with Nextcloud? What I'm finding is that I need to click on it and click OK for the calendar to sync properly but the alert icon never goes away.

The server responded with an error.
The request for account “my.domain” failed.

The server responded with
“501”
to operation CalDAVUpdateShareesQueuableOperation.

Try Again | OK

[d19dotca]

A HTTP 501 means the server didn't understand the function from the request. Reference: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/501

My guess is the NextCloud implementation of CalDAV doesn't support the CalDAVUpdateShareesQueuableOperation operation as it states in the error you included from the client side.

It may be helpful to get logs from both sides to see what each say about it, because sometimes it's easier to piece together the missing parts or reasons why by comparing the logs from each side of the transaction.

If you're sharing calendars, that may be an issue if NextCloud doesn't support it. Reference on an ownCloud repo issue: https://github.com/owncloud/calendar/issues/828

[christiaan]

@d19dotca thanks for that. Sharing calendar is exactly what we're doing. Nextcloud support it, it's built in, but you're right it looks like it's an issue with the implementation, because it used to work for us without this issue.

Can't get my Nextcloud logs to load for some reason.

[christiaan]

@d19dotca this are what the logs say. Does this mean anything to you?

Jul 20 09:22:08 82.155.32.69 - - [20/Jul/2021:08:22:08 +0000] "POST /remote.php/dav/calendars/myusername/test/ HTTP/1.1" 401 557 "-" "macOS/12.0 (21A5284e) CalendarAgent/960"
Jul 20 09:22:09 82.155.32.69 - myusername [20/Jul/2021:08:22:09 +0000] "POST /remote.php/dav/calendars/myusername/test/ HTTP/1.1" 501 276 "-" "macOS/12.0 (21A5284e) CalendarAgent/960"

[nebulon]

@christiaan just some guess, did you maybe share the calendar as read-only? Since it does a POST I assume your client tries to update or create a resource.

[d19dotca]

@christiaan Those two lines don't tell me too much, unfortunately. But I did notice you are using macOS 12.0 which if I'm remembering right is the latest beta of macOS Monterey which isn't actually out yet for the public outside of the beta channels, so I'm wondering if perhaps this issue could be caused by some bugs in macOS Monterey and it's implementation of it which doesn't work with NextCloud for shared calendars? I'm not certain, and I guess it's unlikely since I had found that very similar issue in GitHub for OwnCloud and they were even using an Android client, but who knows. Do you happen to see this issue if using a more supported macOS version (11.x "Big Sur" and lower?) with the built-in Calendar app?

[christiaan]

@nebulon said:

did you maybe share the calendar as read-only?

No they're normal calendars.

@d19dotca said:

Do you happen to see this issue if using a more supported macOS version (11.x "Big Sur" and lower?) with the built-in Calendar app?

Yes, I was having this same problem with Big Sur. Seeing the problem was still there in Monterey actually prompted me to look into it more.