Supervisor 3.3 with Ubuntu 16.04 service start failure

I am on Ubuntu 16.04 using Supervisor 3.2 and am getting the same error when i try to start supervisor with service supervisor start.

I used apt-get install supervisor to install supervisor and it put supervisorctl and supervisord in /usr/bin/.

And my supervisor.service file is pointing at /usr/bin/. I'm stuck.

UPDATE I found the problem, it turns out there was a parsing error in one of my .conf files in /etc/supervisor/conf.d/. Once I fixed that it worked. That error was not at all clear but there is a hint as to how to find it. In there original error output there is a line like

ExecStart=/usr/bin/supervisord -n -c /etc/supervisor/supervisord.conf (code=exited, status=203/EXEC)

Run /usr/bin/supervisord -n -c /etc/supervisor/supervisord.conf from the command line and it will give you a more verbose error.

I fix the problem by edit /lib/systemd/system/supervisor.service, and best to use command install supervisor easy_install supervisor

[Unit]
Description=Supervisord Service

[Service]
ExecStart=/usr/local/bin/supervisord -n -c /etc/supervisor/supervisord.conf
ExecStop=/usr/local/bin/supervisorctl $OPTIONS shutdown
ExecReload=/usr/local/bin/supervisorctl -c /etc/supervisor/supervisord.conf $OPTIONS reload
KillMode=process
Restart=on-failure
RestartSec=50s


[Install]
WantedBy=multi-user.target

The path of supervisord was wrong in default setting, it was /usr/bin. but pip install will put it in /usr/local/bin.