"If Sogo user create event invitation trough webmail with reminder
inside and send it to a Microsoft/Exchange/Outlook user, the
Microsoft/Exchange/Outlook receives the invitation with "not supported
calendar message.ics" attachment to it and is not able to add it to his
calendar."
Copied this from an old ticket:
https://bugs.sogo.nu/view.php?id=4801#c15485
The issue is closed but I can confirm that the bug is active again.
If you remove the reminder the appointment creation to @outlook.de is
working again.
I checked the invite.ics file with different ics validators: passed on 3
different validators. So it looks like it’s created using the rfc
standards.
This is probably more of a Microsoft issue, but it's likely to affect
many SOGo users.
About our SOGo instance:
- integrated in mailcow dockerized current stable version "2025-07"
- SOGo version: 5.12.0
