Supervisor socket error issue

You have to start supervisord before you can use supervisorctl. In my case:

sudo supervisord -c /etc/supervisor/supervisord.conf
sudo supervisorctl -c /etc/supervisor/supervisord.conf

If you started supervisord with a custom path, like this:

sudo supervisord -c /mypath/supervisord.conf

Then you should also start supervisorctl with the same parameter, like this:

sudo supervisorctl -c /mypath/supervisord.conf