Custom domain + HTTPS gives NET::ERR_CERT_COMMON_NAME_INVALID only with apex domain

[alexanian]

Weird error for me. I have a custom domain hosted via Namecheap. I cofigured my A records the way recommended by the troubleshooting docs (see image below) and it _mostly _works.

In particular, all of the following links correctly redirect:

• https://www.catalystbiosummit.com
• http://www.catalystbiosummit.com (redirects to https://www.catalystbiosummit.com/)
• http://catalystbiosummit.com (redirects to https://www.catalystbiosummit.com/)

but:

• https://catalystbiosummit.com doesn’t work, and instead shows a privacy error, “NET::ERR_CERT_COMMON_NAME_INVALID”

The full message I get with the privacy error is:

“This server could not prove that it is  catalystbiosummit.com ; its security certificate is from www.github.com. This may be caused by a misconfiguration or an attacker intercepting your connection.”

What’s up? Is this a mixed content issue? Can I fix this with a redirect somehow?

Screenshot of DNS Config

[mkatwood]

Yo I have been dealing with a similar issue and this ended up solving my problem: https://medium.com/@monarchwadia/github-pages-setting-up-www-subdomain-with-ssl-https-aca9eca371d6

Maybe try this out and see if it does anything for you? Basically in the Github pages repo settings, I just had to make sure “www.” was in my custom domain and “enforce https” was checked. For some reason it wasn’t working when I just had the apex domain entered as the custom domain in settings.

Our problems are different since I was having the opposite problem, where the apex domain was working but it just wouldn’t work solely when using SSL *and* the www subdomain. Worth looking at though!

Hope you manage to fix your issue as well!