After upgrading to Plesk v18.0.76 dovecot keep crashing with the error:
Feb 19 11:59:29 plesk01 dovecot: service=imap, user=redacted@redacted.tld, ip=[1.2.3.4]. Panic: file imap-sieve-storage.c: line 216 (imap_sieve_add_mailbox_event): assertion failed: (ismt->src_box == NULL || ismt->src_box == src_box)Cause
This is a known issue in the dovecot-pigeonhole v2.4.2 shipped with Plesk 18.0.76 related to how certain email clients handle message movement, particularly when the Sieve plugin is involved. The panic is often triggered by specific IMAP client behaviors, such as moving or deleting emails, especially from mobile devices like iPads or Android phones using apps like Thunderbird. The issue seems to stem from a conflict within the internal handling of the source mailbox during the Sieve-related operations. It has been widely discussed on the Dovecot mailing list and Plesk forums.
Workaround
A temp fix is to run the commands below until Plesk can get this issue fixed:
// apply the fix
echo 'mail_attachment_detection_options =' > /etc/dovecot/conf.d/999_fix_crash.conf
// restart dovecot
systemctl restart dovecot