Error 502 bad gateway

This is a customer forum, so we can just offer advice. If you want to open a ticket, login to Cloudflare and then contact Cloudflare Support.

A 502 is usually your host not letting Cloudflare connect. Either due to an internal block or a firewall. Sometimes just an overloaded server.
https://support.cloudflare.com/hc/en-us/articles/218378978-What-should-I-do-after-seeing-a-502-or-504-gateway-error-on-my-site-