Cannot edit calendar event with external attendees (outside organization) — e.g. adding Talk conference fails

[GretaD]

Steps to reproduce

1. Open Nextcloud Calendar and create an event.
2. Add at least one external attendee (email from outside the organization, e.g. user@gmail.com).
3. Save the event.
4. Reopen the event and try to edit it — e.g. click "Add Talk conference" or change any other field.
5. Observe: error appears, changes are not saved.

Expected behavior

i am able to save the event

Actual behavior

an error is shown instead

Calendar app version

6.2.0

CalDAV-clients used

No response

Browser

No response

Client operating system

No response

Server operating system

No response

Web server

None

Database engine version

None

PHP engine version

None

Nextcloud version

No response

Updated from an older installed version or fresh install

None

List of activated apps

Nextcloud configuration

Web server error log

Log file

Browser log

Additional info

No response

[chandrika1993]

Hey @GretaD , I ran into this bug too and had a dig around the code.
The issue is that when an event has external attendees, the CalDAV server tries to look them up as local users when saving and rejects the whole request when it can't find them. I also noticed that the calendar grid was not updating instantly after saving because the server does not return an ETag after a save, which causes an extra request before the UI refreshes.
I will be happy to provide a fix if no one is yet working on it.

[GretaD]

Hello @chandrika1993 a fix would be very much appriciated. Happy to review your PR :)

[GretaD]

closing this ticket as not reproducible starting from the latest version of stable32