Anyone else affected by the below error

---------- Forwarded message ----------
From: Mail Delivery System <MAILER-DAEMON@rat01.safaricombusiness.co.ke>
Date: Mon, Nov 27, 2017 at 3:47 PM
Subject: Delivery Status Notification (Failure)
To: ggitagia@gmail.com


The following message to <XXXXX@XXXXXXXXcom> was undeliverable.
The reason for the problem:
5.1.0 - Unknown address error 550-'Please turn on SMTP Authentication in your mail client. \n(rat01.safaricombusiness.co.ke) [197.248.254.120]:42090 is not permitted to\nrelay through this server without authentication.'

Final-Recipient: rfc822;XXXXX@XXXXXXXXcom
Action: failed
Status: 5.0.0 (permanent failure)
Remote-MTA: dns; [197.248.5.12]
Diagnostic-Code: smtp; 5.1.0 - Unknown address error 550-'Please turn on SMTP Authentication in your mail client. \n(rat01.safaricombusiness.co.ke) [197.248.254.120]:42090 is not permitted to\nrelay through this server without authentication.' (delivery attempts: 0)
--