Sinatra - 504 Gateway Time-out The server didn't respond in time

I am running a sinatra application on server. Ofte开发者_如何学运维n it generates a time out error.

504 Gateway Time-out The server didn't respond in time.

And some time it works well. I could not find out the cause of this. Any one please help me.

This happened because of high load. I've created 2 more instances of this (on haproxy). And increased the time out value. Now it works fine.