Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Tue, 18 Nov 2025 04:06:23 -0500

The original message was received at Tue, 18 Nov 2025 04:06:21 -0500
from m0090839.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 [DS3PEPF000099DC.namprd04.prod.outlook.com 2025-11-18T09:06:23.209Z 08DE240FA9FC6DC7])

   ----- 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 [DS3PEPF000099DC.namprd04.prod.outlook.com 2025-11-18T09:06:23.209Z 08DE240FA9FC6DC7]
550 5.1.1 <[email-masked]>... User unknown
<<< 503 5.5.2 Need rcpt command [DS3PEPF000099DC.namprd04.prod.outlook.com 2025-11-18T09:06:23.209Z 08DE240FA9FC6DC7]