Error 550 But only when sending to one specific email

Error 550 But only when sending to one specific email

From: <mailer-daemon@mail.zoho.com>
To: <p****f@newhopetransport.com>
Date: Mon, 22 Jun 2020 09:47:01 -0500
Subject: Undelivered Mail Returned to Sender
============ Forwarded 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.

d*****r@best-waycargo.com INVALID_ADDRESS, ERROR_CODE :550, ERROR_CODE :Please turn on SMTP Authentication in your mail client.
            sender4-op-o10.zoho.com [136.143.188.10]:17083 is not permitted to relay
            through this server without authentication.



Reporting-MTA: dns; mx.zohomail.com
Arrival-Date: Mon, 22 Jun 2020 09:46:11 -0500

Original-Recipient: rfc822; d****r@best-waycargo.com
Final-Recipient: rfc822; d****r@best-waycargo.com
Status: 550
Action: failed
Last-Attempt-Date: 22 Jun 2020 14:47:01 GMT
Diagnostic-Code: Please turn on SMTP Authentication in your mail client.
            sender4-op-o10.zoho.com [136.143.188.10]:17083 is not permitted to relay
            through this server without authentication.


Received:from mail.zoho.com by mx.zohomail.com
    with SMTP id 159283717140511.198040602566834; Mon, 22 Jun 2020 07:46:11 -0700 (PDT)
Message-ID:<172dc7e68cb.11b77182215203.7675324925881409517@newhopetransport.com>
Date:Mon, 22 Jun 2020 09:46:11 -0500
From:Phil Neudorf <p******f@newhopetransport.com>
To:"dslater" <d****r@best-waycargo.com>
Subject:Test
Content-Type:multipart/alternative;
    boundary="----=_Part_47247_1920350841.1592837171403"
User-Agent:Zoho Mail





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