[Dovecot] Director lmtp timeout errors

Hello,

 I have configured two dovecot servers with director acting as 

lmtp/imap/pop proxy server with 8 dovecot backend servers.

 In our test environment we had no problem, but when we migrated to 

production environment, our mail list server (it delivers mail through lmtp) is having a lot of errors like this:

451 4.4.0 Remote server not answering (DATA output timeout) (in reply to end of DATA command))

 I have found this same issue in some posts to this list, but I 

can't find any solution

 Any idea?

-- Angel L. Mateo Martínez Sección de Telemática Área de Tecnologías de la Información _o) y las Comunicaciones Aplicadas (ATICA) / \\ http://www.um.es/atica _(___V Tfo: 868887590 Fax: 868888337