Heroku SSL 502

Forgot to add earlier “without any warning messages”, right?

Hmm, anyhow though, as you havent set it to “Full (strict)” it should probably work regardless of the certificate’s validity. You also wrote the status is “active”, so it shouldnt be a missing certificate on Cloudflare’s side either.

502 shouldnt be a TLS error however, but rather a generic one regarding the uplink. Have you made sure and/or verified the origin server is reachable from Cloudflare (no firewall entries)?