Postfix was running well untill I decided for some reason to restart since I updated message_size_limit
By doing this
postconf -e message_size_limit=24840000
Stopped it and Now ... Postfix wont start , It keeps on saying
fatal: open lock file /var/lib/postfix/master.lock: unable to set exclusive lock: Resource temporarily unavailable
I tried reverting the change but no luck,
Sep 23 20:47:45 example.com systemd[1]: Starting Postfix Mail Transport Agent...
Sep 23 20:47:45 example.com postfix/postfix-script[13392]: starting the Postfix mail system
Sep 23 20:47:45 example.com postfix/master[13394]: fatal: open lock file /var/lib/postfix/master.lock: unable to set exclusive lock: Resource temporarily unavailable
Sep 23 20:47:46 example.com postfix/master[13393]: fatal: daemon initialization failure
Sep 23 20:47:47 example.com postfix/postfix-script[13395]: fatal: mail system startup failed
Sep 23 20:47:47 example.com systemd[1]: postfix.service: control process exited, code=exited status=1
Sep 23 20:47:47 example.com systemd[1]: Failed to start Postfix Mail Transport Agent.
Sep 23 20:47:47 example.com systemd[1]: Unit postfix.service entered failed state.
Sep 23 20:47:47 example.com systemd[1]: postfix.service failed.
If it would help , I also installed SSL from LetsEncrypt like 2 weeks ago , perhaps that might be the cause of the problem?