Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Fri, 19 Sep 2025 08:50:59 -0400

The original message was received at Fri, 19 Sep 2025 08:50:57 -0400
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 [CY4PEPF0000E9DA.namprd05.prod.outlook.com 2025-09-19T12:50:59.327Z 08DDF4732F66B8D0])

   ----- 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 [CY4PEPF0000E9DA.namprd05.prod.outlook.com 2025-09-19T12:50:59.327Z 08DDF4732F66B8D0]
550 5.1.1 <[email-masked]>... User unknown
<<< 503 5.5.2 Need rcpt command [CY4PEPF0000E9DA.namprd05.prod.outlook.com 2025-09-19T12:50:59.327Z 08DDF4732F66B8D0]