Hi Milos,

Can you enable all logs, reproduce the issue and provide the logs ?

SoDebugBaseURL = YES;
  SOGoDebugRequests = YES;
  ImapDebugEnabled = YES;
  LDAPDebugEnabled = YES;
  PGDebugEnabled = YES;
  SMTPDebugEnabled = YES;

  MySQL4DebugEnabled = YES;
  SOGoUIxDebugEnabled = YES;

Thank you

Sebastien

The problem occurred today on my production server. It is used by thousands of users. I can't work with it as a test machine.
I will try to prepare a similar environment on another machine and copy the data of some of the users who experienced the problem to it.

Sure, thank you Milos

I found relating information:
apache error.log:
[Thu Apr 04 15:36:14.751790 2024] [proxy_http:error] [pid 2831792] (20014)Internal error (specific information not available): [client 1.2.3.4:54281] AH01102: error reading status line from remote server 127.0.0.1:20000, referer: https://webmail.zcu.cz/SOGo/so/useri/Calendar/view
[Thu Apr 04 15:36:14.751829 2024] [proxy:error] [pid 2831792] [client 1.2.3.4:54281] AH00898: Error reading from remote server returned by /SOGo/so/useri/Calendar/eventsblocks, referer: https://webmail.zcu.cz/SOGo/so/useri/Calendar/view

kern.log:
Apr 4 15:36:14 webmail kernel: [1091317.692317] sogod[2819236]: segfault at 1b00000041 ip 00007f1992a5b981 sp 00007ffe6f6c8ef8 error 4 in libobjc.so.4.0.0[7f1992a54000+a000] likely on CPU 10 (core 0, socket 10)
Apr 4 15:36:14 webmail kernel: [1091317.692346] Code: 00 48 8b 41 08 48 8b 00 48 85 c0 75 ef 48 89 fe 31 ff e9 42 fc ff ff 66 90 48 85 ff 74 53 48 8b 06 4c 8b 07 48 89 c1 41 89 c1 <49> 8b 50 40 48 c1 e9 20 41 c1 e1 05 41 01 c9 4c 3b 4a 28 72 12 48

Hi Milos, unfortunately this won't helps.

1/ It may be relative to 0005942, you can try latest master branch ?
2/ If not, you can provide an ics export of your calendar (send it by mail for privacy)

Sebastien