This seems to be related to 0005769

see logs

Hello,
There are several issues about that missing separator that happens sometime, and I've had a look at some point:

C: 4 LIST "" ""
R: * LIST (\Noselect) "." ""
R: 4 OK Completed (0.000 secs)
C: 5 status "INBOXSent" (UIDVALIDITY)
R: 5 NO Mailbox does not exist
C: 6 create "INBOX.Sent"

The delimiter is set when doing the LIST command, in all the cases we can see the delimiter (here it's "."). Then it's the same variable that is used for doing all the following command so I didn't understand how it was possible for it to be missing int the first command (status) but not in the second (create)...

However, could you add in your sogo.conf:
ImapLogEnabled = YES;
It may print some more logs that could help when this problem happens

Hi,

Thanks for the quick response! As ImapLogEnabled didn't do anything, I set ImapDebugEnabled=Yes and this one worked.

I'm waiting for the error to show up again, will update this item when I have new results.

Hello,

See the newly attached file containing corresponding logs from sogo- and imap-server.

Hello,
Thanks for the log alas not new useful information or error. I would have to think a proper way to catch this error and understand why it happens.