I cannot seem to set up the CNAME.

When I attempt to set a subdomain with either media.domain or cdn.domain, I get and error that says those ID have already been used.

When I attempt to set subdomain with anything else, I get the following error:

"Verification failed. Please create CNAME Record for 'pub.spectruminteractivegroup.com' pointing to 'media.publit.io.'"

My DNS host will not allow me to add the trailing dot on 'media.publit.io.' so I don't know if that is the problem or not.