On Thu, 9 Jun 2022, Richard wrote:
> Rather than simply upping the limit I think a reasonable question to
> ask is why/how they are managing to do that. That's a lot of open
> folders.
If this mail client behaves anything like Apple mail clients, these
connection storms can come about when doing global searches.  The mail
clients will march through each mailbox (opening a connection for each
mailbox) looking for a pattern.
If you can narrow this scenario for one specific user (e.g. $user), you
can deep dive what's going on by enabling IMAP session logs for this user
        protocol imap {
                ...
                rawlog_dir = /log/dir/%u
        }
then
        (Make sure this user has write permissions into this directory)
        mkdir /log/dir/$user
After you're done, you can disable logging,
        rm -rf /log/dir/$user
Joseph Tam <jtam.home at gmail.com>