I'm trying to use the migration tool when setting up a new email account with Zoho, but the email migration tool is not recognizing that  SOMETHING.cf  (not the actual domain name) as a valid server name. It just keeps saying "Enter a valid Server Name"  even though the correct server name is entered. 

Should the server name be in some special format? There's no indication of formatting so I just entered the server name as  SOMETHING.cf