I have recently set my server hostname from localhost.localdomain to xx.mydomain.com from the plesk control panel.

However after doing this change postfix has stopped working, I tried restarting and regenerating the config files but to no avail.

I am not familiar with postfix but I believe there is a setting to be changed in main.cf.

Here are the relevant errors I receive:

postfix/postfix-script: starting the Postfix mail system
postfix/master: daemon started -- version 2.8.4, configuration /etc/postfix
postfix/cleanup: fatal: host/service localhost/12768 not found: Name or service not known
postfix/pickup: warning: maildrop/E5559996219: error writing 4FA2C996217: queue file write error
postfix/master: warning: process /usr/libexec/postfix/cleanup pid 15334 exit status 1
postfix/master: warning: /usr/libexec/postfix/cleanup: bad command startup -- throttling

Any ideas?

EDIT

Setting it back to localhost.localdomain makes it work again. The only references to localhost/12768 I can find in main.cf are:

smtpd_milters = inet:localhost:12768
non_smtpd_milters = inet:localhost:12768

Should something be changed here? These two lines stay the same when I change the hostname.

EDIT

If I comment out the two mail filter lines (the ones shown above) and restart, postfix works with the new hostname. However this is obviously not the ideal solution...