Hi,
Probably 'postfix' user cannot login to the database, cause of a wrong password.
Try to manually connect to the database from the command-line:
Code:
mysql -u postfix -p
It seems also that you are using the default settings -- "domain.tld" -- have made the appropriate changes to the config files?
Show you /usr/local/etc/dovecot.conf and /usr/local/etc/dovecont-sql.conf files.
Regards,
D