Access Zoho mail with POP from Mac

Access Zoho mail with POP from Mac

I am setting up a new Zoho account.
I have not yet changed my MX records. 
I want to test first.

I obviously have one address, my zoho administrator address. It currently has One Unread Message.

I want to test that it is possible to access Zoho mail via POP3 from my Mac.

I can access the account.
It does not bring in the one unread message.

Help??