I have an issue that's driving me crazy. Running Ubuntu 12.04 on DigitalOcean, I followed this tutorial to set up Postfix, Dovecot, ViMbAdmin and RoundCube:
Everything has been working fine for almost a week so far until suddenly today my incoming mail started getting stuck in the queue. I can see the emails using postqueue -p but they've just been sitting there for over 5 hours.
I am able to send email to other hosts just fine, but I can't receive emails I send to myself either.
In my mail.err log I keep seeing lots of this:
Apr 8 16:10:30 marcusforsberg master: fatal: master_spawn: exec /usr/lib/postfix/f: Permission denied
But nothing else in the error log, just that line over and over.
The mail.log file keeps giving me this:
Apr 8 15:48:07 marcusforsberg master: fatal: master_spawn: exec > /usr/lib/postfix/f: Permission denied
Apr 8 15:48:08 marcusforsberg postfix/master: warning: process /usr/lib/postfix/f > pid 5841 exit status 1
Apr 8 15:48:08 marcusforsberg postfix/master: warning: /usr/lib/postfix/f: bad > command startup -- throttling
And for each email:
Apr 8 15:46:05 marcusforsberg postfix/qmgr: 7D40416365E: from=, size=5691, nrcpt=1 (queue active)
Apr 8 15:51:40 marcusforsberg postfix/qmgr: 7D40416365E: skipped, still being delivered
Running postqueue -f has no effect, nor has resetting the Postfix config (dpkg-reconfigure postfix), restarting Postfix or rebooting the server (this has worked before when e-mail got stuck).
I've spent the better part of the day researching this but I haven't found much useful. The only change done before this started malfunctioning was that I rebuilt my DigitalOcean droplet from a snapshot. Before this, everything was working just fine. I had seen the "Permission denied" errors regularly as well but I was still able to receive email.
Here is my main.cf for Postfix: http://pastebin.com/hrxhkWZ7
And my master.cf: http://pastebin.com/mV9GcUNi
If anyone has any suggestions or links to solutions I have missed, please do let me know. Or if I should share any other configuration files or logs.
Thanks in advance for any help!
(This is a repost of my question on DO, where I haven't had much luck. I hope that is allowed and that this is even a good place for this question... Please let me know otherwise!)