Client: Windows 10
Sogo Server: Debian GNU/Linux 11 (bullseye)
Sogo version: 5.7.0
Dovecot server: Debian GNU/Linux 10 (buster)
MS Outlook version: 2016 with 32-Bit
Outlook ost-file size: 1,83GByte

MS Outlook with active sync stops synchronization when approximately 90% emails are down loaded
and then stops the synchronization and MS Outlook show the error message "disconnected".
Reset the the sogo cache with "sogo-tool manage-eas listdevices <user>" does not work anymore.
Problem exist also in other previous version of Sogo.

Problem seems to stop in the version 5.6.0.

In all Sogo versions before the problem could be solved mostly by recreating the complete active sync account in Outlook.
Problem seems to appear sporadically on different Windows clients with MS Outlook 2016 and active sync.
MS Outlook PST-repair tool "C:\Program Files (x86)\Microsoft Office\Office16\SCANPST.EXE" does not solve
the problem. Only the new creation of the whole Outlook account solve the problem.

Sogo server syslog show following error message:
Jul 6 13:01:56 sogo1 kernel: [540939.953826] sogod[121988]: segfault at 10 ip 00007f2575076713 sp 00007fff724f3190 error 4 in Mailer[7f257504a000+36000]
Jul 6 13:01:56 sogo1 kernel: [540939.953836] Code: 8b 45 90 48 05 88 00 00 00 48 89 45 b8 c6 45 8f 00 c6 45 8e 01 80 7d 8f 00 0f 84 86 00 00 00 48 8b 45 b8 48 8b 00 48 83 c0 10 <8b

It's unclear where is coming this error message and if this error message is related with the problem or not.