Error 502 Bad gateway.!

There is a problem with your origin server. You’ll need to contact your hosting provider or correct it. https://support.cloudflare.com/hc/en-us/articles/218378978-What-should-I-do-after-seeing-a-502-or-504-gateway-error-on-my-site-

curl -Ik --resolve hubtitle.com:443:your.origin.ip.address https://hubtitle.com
HTTP/2 502
server: nginx
date: Wed, 16 May 2018 20:43:18 GMT
content-type: text/html
content-length: 166
x-xss-protection: 1; mode=block
x-content-type-options: nosniff