My subdomain don't work on Cloudflare

For some reason my subdomain won’t work when I add A record pointed to the server IP. IP is different of that on my main domain, because I use 2 vm cloud instances - one for main site and one for the forum. If I use name servers of an hosting provider and add A records from their Cpanel, everything is working fine.i don’t understand why only my main domain is working with Cloudflare. Any help, please!

If a site works with HTTPS before adding it to Cloudflare, then it should work once added to Cloudflare. What do you mean “don’t work”? Is there an error you’re seeing?

My main domain name is https://glas.ga
My forum is located in subdomain diskusii.glas.ga
Main domain is pointed to one server IP adress, subdomain is pointed with an a record to another server.
Main site is working fine with Cloudflare, subdomain don’t.
Subdomain works perfect on another hosting name servers with an A record from Cpanel to the same IP

I see the following headers when I make a request

< set-cookie: __cfduid=d791f45bdb8061baf1e79b9016f13102a1614118008; expires=Thu, 25-Mar-21 22:06:48 GMT; path=/; domain=.glas.ga; HttpOnly; SameSite=Lax; Secure
< location: https://diskusii.glas.ga/

They indicate that you have “Always Use HTTPS” enabled in your Cloudflare account (which is good), but that you have enabled SSL Mode Flexible (which is not good) and that your Origin is redirecting to HTTPS (again this is good).

Is the SSL Mode on the SSL/TLS tab of the dashboard set to Flexible?

You can set a page rule to set the SSL mode for the subdomain to Full or Full (Strict). The URL match will be https://diskusii.glas.ga/*

You should also investigate if any other hostnames are set Flexible, and make sure that their Origins will respond to HTTPS requests, and set the SSL mode to Full or better on the SSL/TLS tab.

3 Likes

Thank you! I set a page rule and now everything is working fine!