Unable to enforce HTTPS for my website

Enforce HTTPS — Not yet available for your site because the certificate has not finished being issued.
Please allow 24 hours for this process to complete.

The checkbox for the above option in my portfolio repository is unable to be checked. 

I have the same problem, in my case the website has been running for almost two days but I’m still getting that. I have made sure that DNS settings are correct and also tried recreating the CNAME twice. How long does it take to enable it?

I also have same problem. What should I do?