I realized that my mailbox quoata after mgiration was not correct and only took new emails into account. Cause of some bad circumstances though i had ispconfig 3.1dev installed and solved the problem by adding mail_plugins = $mail_plugins quota in dovecot.conf and recalculatet the quota with doveadm. Now I updated with ispconfig_update.sh to 3.1.15p3 and now I would like to ask if I get in trouble cause of the earlier manual configuration change of dovecot.conf and the quata recalculate. I would guess no, cause if I didnt missed it it looks like the ispconfig upgrade scirpt wrote a new dovecot.conf so that my changes might be undone Debian Buster Apache
The dovecot.conf change was probably not necessary and the dovecot.conf written by ISPConfig enables mail quota, the recalculation of the quota was most likely the reason for your issue.
