Thanks again Jeremy,

I have added the missing colon to the config you have highlighted, However am still not able to send email below is the output from the journalctl. Also why am I getting a " Active: (exited) ?

root@observium ~# systemctl status postfix*
* postfix@-.service - Postfix Mail Transport Agent (instance -)
   Loaded: loaded (/lib/systemd/system/postfix@.service; disabled; vendor preset: enabled)
   Active: active (running) since Mon 2019-09-16 09:39:49 EST; 5min ago
     Docs: man:postfix(1)
  Process: 902 ExecStart=/usr/sbin/postmulti -i - -p start (code=exited, status=0/SUCCESS)
  Process: 591 ExecStartPre=/usr/lib/postfix/configure-instance.sh - (code=exited, status=0/SUCCESS)
    Tasks: 16 (limit: 4915)
   CGroup: /system.slice/system-postfix.slice/postfix@-.service
           |-1103 /usr/lib/postfix/sbin/master -w
           |-1117 qmgr -l -t unix -u
           |-1124 trivial-rewrite -n rewrite -t unix -u -c
           |-1239 trivial-rewrite -n rewrite -t unix -u -c
           |-1303 pickup -l -t unix -u -c
           |-1690 cleanup -z -t unix -u -c
           |-1694 local -t unix
           |-1718 cleanup -z -t unix -u -c
           |-1719 cleanup -z -t unix -u -c
           |-1725 local -t unix
           |-1760 local -t unix
           |-1795 bounce -z -t unix -u -c
           |-1796 bounce -z -t unix -u -c
           |-1802 bounce -z -t unix -u -c
           |-1807 local -t unix
           `-1847 bounce -z -t unix -u -c

Sep 16 09:45:13 observium postfix/bounce[1796]: 1E164E0388: sender non-delivery notification: A6803E13E9
Sep 16 09:45:13 observium postfix/qmgr[1117]: A67D0E128F: from=<ifax@mydomain.com>, size=50661, nrcpt=1 (queue active)
Sep 16 09:45:13 observium postfix/local[1807]: 2E92FE1294: to=<provenit@mydomain.com>, orig_to=<ifax@mydomain.com>, relay=local, delay=4.6, delays=0.07/4.4/0/0.11, dsn=5.1.1, status=bounced (unknown user: "provenit")
Sep 16 09:45:13 observium postfix/qmgr[1117]: 1E164E0388: removed
Sep 16 09:45:13 observium postfix/bounce[1795]: 1E2D7E117E: sender non-delivery notification: A67D0E128F
Sep 16 09:45:13 observium postfix/qmgr[1117]: A6803E13E9: from=<ifax@mydoamin.com>, size=48733, nrcpt=1 (queue active)
Sep 16 09:45:13 observium postfix/local[1725]: 2E8DFE0003: to=<provenit@mydomain.com>, orig_to=<ifax@mydomain.com>, relay=local, delay=4.6, delays=0.07/4.4/0/0.11, dsn=5.1.1, status=bounced (unknown user: "provenit")
Sep 16 09:45:13 observium postfix/qmgr[1117]: 1E2D7E117E: removed
Sep 16 09:45:13 observium postfix/cleanup[1690]: C2D78E117E: message-id=<20190916144513.C2D78E117E@mydomain.com>
Sep 16 09:45:13 observium postfix/cleanup[1718]: C2CBDE0388: message-id=<20190916144513.C2CBDE0388@mydomain.com>

* postfix.service - Postfix Mail Transport Agent
   Loaded: loaded (/lib/systemd/system/postfix.service; enabled; vendor preset: enabled)
   Active: active (exited) since Mon 2019-09-16 09:39:49 EST; 5min ago
  Process: 1118 ExecStart=/bin/true (code=exited, status=0/SUCCESS)
 Main PID: 1118 (code=exited, status=0/SUCCESS)
    Tasks: 0 (limit: 4915)
   CGroup: /system.slice/postfix.service

Sep 16 09:39:49 observium systemd[1]: Starting Postfix Mail Transport Agent...
Sep 16 09:39:49 observium systemd[1]: Started Postfix Mail Transport Agent.