Can't receive emails

Can't receive emails

Set up a domain, set it up as explained in Godaddy, adding new cname to verify which went okay, then added the new MX with priority 10, Host at @, Points to mxzohomail, and below it 20, @, mx2zohomail. 

Trouble is, whenever I send myself a test email from gmail, I'm getting it rejected with:

 550 550 #5.1.0 Address rejected my address (state 14).

Also tried it with my godaddy email account, and that bounces the email back with:

Remote host said: 550 #5.1.0 Address rejected.

Any ideas why? I'd really like to use Zoho, but if I can't get it to work, I'll have to go back to Godaddy mail, which I don't like, but works.

Thanks