Some time back (maybe several weeks ago) I stopped receiving email notifications for updates available (or anything for that matter). It used to work and my credentials haven't changed. When I tried to send a test email I don't receive anything.
This is the contents of /var/log/mail.log after a restart of omv.
Code
Apr 26 22:03:48 straitdeb postfix/postfix-script[1242]: fatal: mail system startup failed
Apr 26 22:03:47 straitdeb postfix/master[982]: fatal: daemon initialization failure
Apr 26 22:03:46 straitdeb postfix/master[985]: fatal: open lock file /var/lib/postfix/master.lock: cannot open file: Permission denied
Apr 26 22:03:46 straitdeb postfix/postfix-script[981]: starting the Postfix mail system
Apr 26 22:03:46 straitdeb postfix/postfix-script[959]: warning: not owned by postfix: /var/lib/postfix/./master.lock
Apr 26 22:03:46 straitdeb postfix/postfix-script[958]: warning: not owned by postfix: /var/lib/postfix/./prng_exch
It looks like something is broken but I don't know what to do to recover. Everything else in OMV is working fine.
Any help with getting email notifications working again would be much appreciated.