Emails are not being set from main account

Emails are not being set from main account

Hey,

I have a main account which is the admin account also.
When I want to send emails from that main account, it works fine.
But I could not receive emails at that main account.

Delivery to the following recipient failed permanently:

      sales@saaqisports.com

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the server for the recipient domain saaqisports.com by mx.zoho.com. [165.254.168.50].

The error that the other server returned was:
550 5.1.1 < sales@saaqisports.com> User unknown


How to fix this issue?