This is missing postfix config of mailbox dir, let see what else ?
Recommended is to use the directory format to store email rather than the the older mbox format. The Maildir format is well supported by Dovecot and has some advantages (no locking, allows for easy incremental back-ups and restoring of individual messages.) So you’ll need to assign a directory.
Convention is to store mail in a
~/Maildir directory in a users home directory, but nothing prevents you from using another (hidden) directory.
You configure both the Maildir format as well as it’s location with the postfix home_mailbox setting:
sudo postconf -e "home_mailbox = Maildir/"https://serverfault.com/questions/639908/change-location-of-maildir?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa
smtpd_sasl_auth_enable = yes smtpd_sasl_security_options = noanonymous smtpd_sasl_local_domain = $myhostname smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks, reject_unauth_destination broken_sasl_auth_clients = yes smtpd_sasl_type = dovecot smtpd_sasl_path = private/auth