GitHub Pages HTTPS unavailable for custom domain jgmechanic.co.uk despite successful DNS check

[JGMechanic]

🏷️ Discussion Type

Question

💬 Feature/Topic Area

Pages

Body

I am trying to enable HTTPS for my GitHub Pages custom domain jgmechanic.co.uk.
Repository: JGMechanic/JG-mechanic
What did you expect to happen?
After configuring the custom domain and receiving “DNS check successful”, I expected GitHub Pages to provision an HTTPS certificate and allow me to enable “Enforce HTTPS”.
What happened instead?
GitHub Pages continues to show:
“Enforce HTTPS — Unavailable for your site because your domain is not properly configured to support HTTPS (jgmechanic.co.uk)”
The domain reaches GitHub Pages, but when visiting https://jgmechanic.co.uk the browser reports that the certificate being presented is for *.github.io, not jgmechanic.co.uk.
I have already verified:

• GitHub Pages reports “DNS check successful”.
• The custom domain is verified in my GitHub account.
• Repository CNAME file contains exactly jgmechanic.co.uk.
• Apex A records are:
  • 185.199.108.153
  • 185.199.109.153
  • 185.199.110.153
  • 185.199.111.153
• Public Google DNS returns all four GitHub Pages A records.
• There are no AAAA records.
• www.jgmechanic.co.uk CNAME publicly resolves to jgmechanic.github.io.
• There are no CAA records restricting certificate issuance.
• There is no DS record/DNSSEC validation issue.
• app.jgmechanic.co.uk is also hosted on GitHub Pages and HTTPS works correctly there.
  I have already removed and re-added the custom domain once, but the problem remains.
  Question:
  Is there anything else that could prevent GitHub Pages from provisioning the TLS certificate for the apex domain? Is there a way for the certificate provisioning process for jgmechanic.co.uk to be re-triggered?
  I can provide screenshots of the GitHub Pages settings, DNS records, and the browser certificate error if required.

[kgeminicdev]

One of your four apex A records has a typo. Your post lists 185.199.108.153, but the live record is 185.190.108.153 (190, not 199). Your own nameserver returns it, and so does Google DNS:

> nslookup -type=A jgmechanic.co.uk dns1.uk2.net
Name:    jgmechanic.co.uk
Addresses:  185.199.110.153
            185.190.108.153   <-- should be 185.199.108.153
            185.199.111.153
            185.199.109.153

185.190.108.153 isn't a GitHub Pages address and doesn't answer HTTP. A request for your site sent to it times out, while the same request to 185.199.108.153 returns 200. To issue the certificate, GitHub's certificate authority has to reach your domain over HTTP, and with one record pointing nowhere that check keeps failing. Browsers mostly pick one of the three good IPs, which is why the site loads and the DNS check looks fine. app. and www. work because they're CNAMEs to jgmechanic.github.io, not A records.

To fix it:

1. At uk2.net, change 185.190.108.153 to 185.199.108.153.
2. Wait for the old record to expire (your zone uses a 30-minute TTL). nslookup jgmechanic.co.uk 8.8.8.8 should show only 185.199.x.153 addresses.
3. In Settings → Pages, remove the custom domain, save, then add jgmechanic.co.uk again. That restarts certificate provisioning. It can take up to an hour or so, then Enforce HTTPS becomes available.