SSL/TLS, Origin Certificates and 502 Bad Gateway

No, no redirects. I only have a simple php file in the public folder just to test things out. So i’m keeping things as simple as possible so that it’s easier to debug.

when the hostname is proxied and set to Full (Strict) ssl and using the CA origin cert, I get the 502 error and it says that the certificate is valid and it’s details are:

Common Name (CN) R3
Organization (O) Let’s Encrypt
Organizational Unit (OU)
Issued On Thursday, January 6, 2022 at 6:26:23 AM
Expires On Wednesday, April 6, 2022 at 7:26:22 AM

But obviously the page is not loading.

I also worked with the hosting provider to solve the issue but they say there’s no issue with the certificate installation (and I can confirm that by setting encryption to Off) and that on their side there is nothing blocking Cloudflare IP’s, which I have to agree with since it works if I set the encryption to Flexible and keep the hostname proxied.

I checked all of the other potential issues from the tutorial you provided. There are plenty of resources available and the ip’s are not blocked.

It’s interesting that I have a second domain hosted with the same provider and using a cPanel, Inc. issued certificate which works fine with Full (strict) encryption. So apparently there’s some issue with the Cloudflare issued certificate, as if Cloudflare does not trust it’s own certificate.

By the way, thank you for taking the time to reply.