502 Bad Gateway nginx

Hello people good night!

I have a gigantic problem

I am new to EE, get install yesterday (yes yesterday) some websites … however today I woke up and all sites are offline with the error 502 Bad Gateway nginx, AND I DO NOT KNOW WHAT TO DO, TO SEARCHING THE FORUM AND THE COMMANDS … but nothing is certain, someone who has experienced this problem can help me? I have less than 30 hours to solve this problem.

Have you tried rebooting the server?

yes , more than 10 times

Can’t further help you without logs.