Reason of getting this: There is multiple reasons, what I found is that my supervisor was got corrupted due to the server going down continuously by power tripping.
solution: Remove the supervisor first and then reinstall it.
Steps:
sudo apt-get remove supervisor
sudo apt-get remove --auto-remove supervisor
sudo apt-get purge supervisor
sudo apt-get purge --auto-remove supervisor
Link for the above can be found here :
https://www.howtoinstall.co/en/ubuntu/trusty/supervisor?action=remove
