Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Fri, 19 Dec 2025 07:42:02 -0500

The original message was received at Fri, 19 Dec 2025 07:42:01 -0500
from m0090833.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 [BN2PEPF000044A4.namprd02.prod.outlook.com 2025-12-19T12:42:02.662Z 08DE3B27C08E7C73])

   ----- Transcript of session follows -----
... while talking to lairdtech-com.mail.protection.outlook.com.:
>>> DATA
<<< 550 5.4.1 Recipient address rejected: Access denied. For more information see https://aka.ms/EXOSmtpErrors [BN2PEPF000044A4.namprd02.prod.outlook.com 2025-12-19T12:42:02.662Z 08DE3B27C08E7C73]
550 5.1.1 <[email-masked]>... User unknown
<<< 503 5.5.2 Need rcpt command [BN2PEPF000044A4.namprd02.prod.outlook.com 2025-12-19T12:42:02.662Z 08DE3B27C08E7C73]