[Dovecot] Passdb disconnected unexpectedly when trying to do Director with LMTP

[Mark Zealey]

Hi there,

I'm running Dovecot 2.0.16 just set up the director with cut&paste from 
the wiki. It's working & running fine for pop/imap connections (as 
verified by doveadm director status user), however when I specify 'RCPT 
TO' for a (tcp) lmtp connection straight away I get:

451 4.3.0 <x...@yyy.com> Temporary user lookup failure

and in the logs:
2012-02-11T14:22:54+00:00 xxx dovecot: lmtp(27997): Error: passdb 
lookup(x...@yyy.com): Disconnected unexpectedly

I'm sure this is an obvious issue for someone who's come across it 
before. The /var/run/dovecot/director-userdb socket is on the system; 
exactly the same permissions as the standard auth-userdb

Here are the relevant bits of my config (I'm setting lmtp to listen on a 
different port than normal). Backend password database is mysql if that 
makes any difference.

lmtp_proxy = yes

service lmtp {
  inet_listener lmtp_test {
    port = 2450
  }
}
protocol lmtp {
  auth_socket_path = director-userdb
}

Thanks,

Mark