where could that be called from ?
From the default passdb/userdb sql settings. You haven't set one of password_query, user_query or iterate_query and it's trying to use the default which doesn't of course work with your database.
thanks
cd /etc/dovecot
grep password_query *
dovecot-sql.conf:password_query = SELECT username as user, password, '/var/mail/vhosts/%d/%n@%d' as userdb_home, **TRIM**
# grep user_query *
dovecot-sql.conf:user_query = SELECT concat('/var/mail/vhosts/', maildir) as home, concat('maildir:/var/mail/vhosts/', maildir) as mail, **TRIM**
dovecot-sql.conf:user_query = SELECT '/var/mail/vhosts/%d/%n@%d' as home, 'maildir:/var/mail/vhosts/%d/%n@%d' as mail, **TRIM**
OOPS, I seem to have duplicate user_query with my two 'user_query', it's the last one in the file that wins, yes ? so, I should remove the 1st one
# grep iterate_query * #
none. so, I need some 'iterate_query' inserted in my dovecot-sql.conf ?
-- Voytek