"unknown user - trying the next userdb" Info in log

I’ve set up a new mail server. Auth-worker is giving me this error all the time:

auth-worker(11160): Info: passwd(sales@bordo.com.au mailto:sales@bordo.com.au,10.0.0.54,<YSFoAYHAGoLAqAEo>): unknown user - trying the next userdb

Next line is from imap-login with successful login.

Using MySQL as user database.

Auth-sql.comf.ext is:

passdb { driver = sql

# Path for SQL configuration file, see example-config/dovecot-sql.conf.ext args = /usr/local/etc/dovecot/dovecot-sql.conf.ext }

# "prefetch" user database means that the passdb already provided the # needed information and there's no need to do a separate userdb lookup. # userdb { driver = prefetch }

userdb { driver = sql args = /usr/local/etc/dovecot/dovecot-sql.conf.ext }

# If you don't have any user-specific settings, you can avoid the user_query # by using userdb static instead of userdb sql, for example: # #userdb { #driver = static #args = uid=vmail gid=vmail home=/var/vmail/%u #}

Any ideas why it is gives me this error before logging in? Where should I look?

Thanks,

James.