553 Relaying disallowed

553 Relaying disallowed

I recently setup my business/custom domain email with Zoho. And when I try to send email via one of the setup accounts, I get following error:

Your message did not reach some or all of the intended recipients.

 

      Subject:    FW: XXXXXXXX

      Sent: 05/11/2014 14:48

 

The following recipient(s) cannot be reached:

 

      'xxxxxxx@xxxxxx.com' on 05/11/2014 14:48

            553 Relaying disallowed