Why Can I Not Send Mail From Another E-Mail to My "@zoho.com" E-Mail ??

Why Can I Not Send Mail From Another E-Mail to My "@zoho.com" E-Mail ??

I attempted to send a test email to my newly created account "******@zoho.com" and I received an e-mail response saying;
" Delivery to the following recipient failed permanently:

    ******@zoho.com

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 550 550 5.1.1 <******@zoho.com>... User unknown (state 14)."



Why is that ?? Do I not have an e-mail address @zoho.com ?? It has the e-mail address displayed at the top of the 
zoho Mail page.