Shall I point CNAME to CDN hostname for SSL validation?

Yes, you have to point your CNAME to our hostname before adding it to the console. If the CNAME is not pointed correctly to our hostname, the SSL won’t start the deployment.

If your CNAME is cdn.yourdomain.com then you have to point it to our hostname.

eg: cdn.yourdomain.com -> push111.5centscdn.com

You can refer to these KBs for adding CNAME In the console

How to add Cname to VoD push/pull zone?

How to add Cname to HTTP push/pull zone?

How to set up CName for Live streams or DVR?