For those that are experiencing this [similar] issue, CDN managed certificates are not provided for APEX/root level domains. You will have to use your own certificate brought from a CAA to enable HTTPS. See the follow docs for reference:
- https://learn.microsoft.com/en-us/azure/cdn/cdn-custom-ssl?tabs=option-2-enable-https-with-your-own-certificate
- https://learn.microsoft.com/en-us/azure/cdn/cdn-troubleshoot-allowed-ca
Regards,
Ryan