[SOGo] Busy/Free not working reliably after upgrade

[Valentina Paganin]

Hello,

we're using SOGo as part of a mailcow-dockerized suite on a debian 11 
bullseye VM running on Oracle oVirt.
I already wrote to them and they said I had to report this bug to SOGo 
directly.

That's our scenario:
in October, we upgraded the suite and enabled the SOGo URL encryption 
feature.
Unfortunately, we found that, when inviting people to a calendar via 
Sogo, busy/free information does not show for someone when the mail is 
being encrypted in the url.
Also, API call to the free/busy information is always made with the 
plain mail address, eg |Oct 21 17:10:18 mymailserver 
mailcowdockerized-nginx-mailcow-1[680] 192.168.-.- - - 
[21/Oct/2025:17:10:18 +0200] "GET 
/SOGo/so/mymail@mydomain/freebusy.ifb/ajaxRead?eday=20251026&sday=20251013 
HTTP/2.0" 200 402 "https://mymailserver.mydomain/"; "Mozilla/5.0 (X11; 
Linux x86_64; rv:143.0) Gecko/20100101 Firefox/143.0"
|Finally, sometimes in the logs we see the line |[ERROR] 
<0x0x7f772ab8dca0[SOGoUser]> URL Decryption error : Could not decrypt|, 
which is partially related to the issue (that is to say, sometimes we 
see in the logs near some calendar related actions and sometimes not).

Steps to reproduce:
Open Sogo webUI, create an event inviting someone. Sometimes the 
busy/free information, either for the creator or the invitee is blank.
If it is blank for the creator, checking the url in the browser shows 
that the email is encrypted.

Mailcow got a release update earlier in December, and we're now running 
SOGo 5.12.4, but the problem is still present.

Did someone else experience the same behaviour or have any idea what's 
wrong?

Thanks and regards.