External attendees cannot accept invitations

[scheinercc]

Same problem here. Checked settings/admin/logging, but nothing gets logged. Is the nextcloud.log a different log file?

Possibly same issue:

Error updating event participation by invited attendees in calendar

Hello, when people I invite to a meeting click on the lin to accept or decline the invitation, they land to a page that says “An error occurred while updating the status of your participation. Please contact the administrator directly.” (translation from italian…) any hints on how to solve this issue ? thanks!