Request Time Out - Nginx / Gunicorn Issue

Hi,
I am getting the error “Request Time Out” from last 2 days,
Full Error :

This site can’t be reached
erp.domain.com took too long to respond.
Search Google for erp tboss info desk
ERR_CONNECTION_TIMED_OUT

In the past it was working fine but don’t know why this error occurs,
I checked in depth then realized when my CPU performance reaches 100% it popups the error that Request Time Out, after that i’ve upgrade my CPU from 1 Core to 4 Cores & 3Gb Ram to 6Gb Ram, but error is still the same.
& i think gunicorn is eating my CPU performance but i don’t know why?
In below picture it is eating 13% but sometimes it reaches at 100%

gunicorn

I’ve also tried to increase number of Gunicorn workers from 3 to 4 and 5 but still the same problem.
Please help.

Try this…