When a new Email Mailbox is created the mail_user.maildir_format column stays empty
Version: ISPConfig 3.1.1p1 Dovecot: 2.1.7
E-Mail login stopped working for freshly created Email Mailboxes after the upgrade to ISPConfig 3.1.1p1.
I received the following mail.log errors
Initialization failed: Initializing mail storage from mail_location setting failed: Unknown setting
After some investigation I found out that freshly created E-Mail-Accounts have an empty mail_user.maildir_format column in the database, manually setting it back to "maildir" fixes the issue.