I received the following bounce back, and confirmed the recipient is receiving emails form others. I have successfully emailed the recipient in the past. What can I do to solve this?

Full message:

This message was created automatically by mail delivery software.
A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. 
[recipient address]  INVALID_ADDRESS, ERROR_CODE :550, ERROR_CODE :5.1.0 Mail system is not configured to accept that recipient



Received:from [192.168.1.2] (173.94.52.7 [173.94.52.7]) by  mx.zohomail.com
with SMTPS id 1549462832586350.4688669881283; Wed, 6 Feb 2019 06:20:32 -0800 (PST)
Message-ID:<[address] >

Date:Wed, 6 Feb 2019 09:20:30 -0500
From:[address]
To:[address]
Subject:Test
Content-Type:multipart/alternative;
boundary="Apple-Mail=_0D555FE2-337F-4267-84EB-87516C2A37F8"