Nginx error 502 Bad Gateway nginx 1 16 0

Question

Hi,

I was configuring the email server, then rebooted the server and now I'm getting error 

502 Bad Gateway nginx/1.16.0

Answer 1

This typically indicates that a back-end service is not listening, which Nginx is relying on to serve the content. Check your nginx logs under /var/log/nginx and perhaps share the error.log