Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Thu, 8 Jan 2026 01:02:01 -0600

The original message was received at Thu, 8 Jan 2026 01:02:00 -0600
from m0132737.ppops.net [127.0.0.1]

   ----- The following addresses had permanent fatal errors -----
<[email-masked]>
    (reason: 550 5.4.1 Recipient address rejected: Access denied. For more information see https://aka.ms/EXOSmtpErrors [DS3PEPF000099E1.namprd04.prod.outlook.com 2026-01-08T07:02:01.207Z 08DE48E435CC9262])

   ----- Transcript of session follows -----
... while talking to regalbeloit.mail.protection.outlook.com.:
>>> DATA
<<< 550 5.4.1 Recipient address rejected: Access denied. For more information see https://aka.ms/EXOSmtpErrors [DS3PEPF000099E1.namprd04.prod.outlook.com 2026-01-08T07:02:01.207Z 08DE48E435CC9262]
550 5.1.1 <[email-masked]>... User unknown
<<< 503 5.5.2 Need rcpt command [DS3PEPF000099E1.namprd04.prod.outlook.com 2026-01-08T07:02:01.207Z 08DE48E435CC9262]