Delivery to the following recipient failed permanently:

Delivery to the following recipient failed permanently:

I keep getting this message when I am testing my email

Delivery to the following recipient failed permanently:  Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the server for the recipient domain  chasingthedonkey.com  by mx.chasingthedonkey.com .

I am guessing that something is not set up right. But what?

Thanks.