After migration postfix does not accept mail

[hgmichna]

I have migrated to a new server running Plesk 11.0.9 with postfix 2.7.1-1+squeeze1. On the old server email worked perfectly well, but on the new one I have this problem.

When I try to send mail from Thunderbird or K-9, I receive an error mail back, essentially with the message:

451 4.3.0 Error: queue file write error

Following a hint from somebody who apparently does not understand the problem fully, I changed the line

submission inet n - - - - smtpd -o smtpd_enforce_tls=yes -o smtpd_tls_security_level=encrypt -o smtpd_sasl_auth_enable=yes -o smtpd_client_restrictions=permit_sasl_authenticated,reject -o smtpd_sender_restrictions= -o smtpd_proxy_filter=127.0.0.1:10025

into

submission inet n - - - - smtpd -o smtpd_enforce_tls=yes -o smtpd_tls_security_level=encrypt -o smtpd_sasl_auth_enable=yes -o smtpd_client_restrictions=permit_sasl_authenticated,reject -o smtpd_sender_restrictions=

This solves the problem, but only by creating a new one. I have removed the smtpd_proxy_filter function that I do not want to remove. Therefore I am looking for help from somebody who understands the cause of the problem, and I hope to find somebody here.

I have changed postfix to verbose logging, but even so the log is meaningless, at least for me. Please see the attached text file. It contains the complete error mail and the relevant log excerpt.