The majority of our CDN providers offer Free SSL certificates, either issued by their own Certificate Authority (Amazon and Cloudflare) or via the free Let's Encrypt
In order for the CDN Provider to install a Free SSL certificate, the domain needs to first be pointing at the correct name servers, as these are Domain Validated Certificates issued through automated processes.
After pointing the name servers, it can take up to 24 hours for their automated systems to detect that the site is pointed to the correct IP address and to then request and issue the certificate.
It depends on the automated processes that they use to do this as to how long it can take, as well as how many other certificate requests they are monitoring at the same time.
You can test the validity and correct issuance of the SSL using this free tool from SSL Shopper: https://www.sslshopper.com/ssl-checker.html
Please allow 24 hours after setting the name servers before opening a ticket related to SSL issues.