Hopefully you all can help!

I've been to hundreds of threads over the last few days trying to puzzle this out, with no luck.

The problem:

1. Caddy v2 with acme HTTP-1 ACME challenge (Changed from TLS-ALPN challenge)
2. Cloudflair DNS with proxy ON
3. All cloudflair https is off
4. This is a .co domain

Any attempt to get certificates fails with an invalid challenge response. If I try and navigate (or curl) to the challenge directly I always get SSL validation errors as if all the requests are trying to upgrade to HTTPS.

I'm kind of at my wit's end here and am running out of things to try.

If I turn Cloud flare proxy off and go back to TLS-ALPN challenge, everything works as expected. However I do not wish to expose myself directly and want to use the proxy.

What should I be doing?

I have now solved this by using Cloudflair DNS ACME challenge. Cloudflair SSL turned back on. Everything works as expected now, I can have external clients terminate SSL at cloudflair, cloudflair communicate with my proxy through HTTPS, and have internal clients terminate SSL at caddy.