When sshwifty is reverse proxied with a subdomain on cloudflare I have a 502 Bad gateway error :

This only happens if the dns record is proxied.

According to cloudflare, it could be due to the content-lenght header
https://developers.cloudflare.com/support/troubleshooting/http-status-codes/cloudflare-5xx-errors/error-502-504/

Disabling automatic https rewrites fixes it.

My reverse proxy is caddy