Xerox Phaser 6128MFP Fax can send but not receive

Using faxtoy.net, I can confirm that the fax can send because the paper that I fax out appears on that website.

When receiving, I was using faxzero.com to send documents and although I receive confirmation from that website that the fax was successful but I never recieved anything.

How can I fix it? Do I have to change some settings on the Xerox Phaser 6128MFP?