Request Time Out - Nginx / Gunicorn Issue

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

This site can’t be reached took too long to respond.
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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%


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…