Copy Website - Website in Plesk grayed out

I've searched everywhere and can't find an answer. So I apologize if this is already answered somewhere.

When I go to copy a website, the option to use "Website in Plesk" is grayed out and unavailable. The option to use "FTP Storage" is available. Can someone please point me in the right direction to make "Website in Plesk" available?

Thank you in advance