I also tried with 2 separate domains in Gitlab : effectivecoding.fr and www.effectivecoding.fr, but the lets’s Encrypt certificate can not be validated for the second domain, and so https is not working.
Hi @Sylvain, did you manage to solve this issue? I have the same problem (also using OVH) and none of the solutions I found on the forum helps I added my root domain with DNS A record and TXT verification successfully (so https://mydomain.com works fine and is encrypted), but cannot do the same for www.mydomain.com. I tried:
adding www.mydomain.com as New Domain and and TXT verification passed, but I can’t validate Let’s Encrypt and when I enter www.mydomain.com I got error “DNS_PROBE_FINISHED_NXDOMAIN” (in all browsers and devices). Only if I add DNS A record it works, but it means I treat www the same as my root domain, is that correct?
Also I didn’t understand why the documentation suggest adding both TXT and CNAME for subdomain www.example.com - when I try to do this in my DNS zone I got error stating I can’t add both TXT and CNAME records for one subdomain (sorry if it’s obvious, but I’m a total rookie).