[Dovecot] Errors in dovecot 1 beta7

[Oliver Schulze L.]

I see these errors talso:
May  6 09:02:10 mail dovecot: pop3-login: Disconnected: Inactivity: 
rip=::ffff:xx.xx.xx.13, lip=::ffff:xx.xx.xx.1
May  6 09:02:10 mail dovecot: auth(default): Master request 21566.1 not 
found
May  6 09:02:10 mail dovecot: pop3-login: Disconnected: Inactivity: 
user=<user2>, method=PLAIN, rip=::ffff:xx.xx.xx.12, lip=::ffff:xx.xx.xx.1
May  6 09:02:10 mail dovecot: pop3-login: Master sent reply with unknown 
tag 1
May  6 09:02:10 mail dovecot: child 21566 (login) returned error 89
May  6 09:02:13 mail dovecot: pop3-login: Login: user=<user1>, 
method=PLAIN, rip=::ffff:xx.xx.xx.10, lip=::ffff:xx.xx.xx.1

What does "Master request 21566.1 not found" means?

Many thanks
Oliver

-- 
Oliver Schulze L.
<oliver at samera.com.py>