I followed the instructions located at  https://adminconsole.wiki.zoho.com/domains/Editing-your-DNS-details.html

I have one domain added to my control panel ccfdis.com

I created a cname called office.ccfdis.com directed to mail.zoho.com

I went back into my Zoho control panel to add office.ccfdis.com but it says I have to purchase a domain. Why do I have to purchase another domain if its the same domain ccfdis.com? Its just a subdomain to allow for logging into Zoho?

Please help.

Thank you,