Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Thu, 11 Sep 2025 08:13:26 +0200

The original message was received at Thu, 11 Sep 2025 08:13:25 +0200
from m0096064.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 [MR1PEPF00000D5A.FRAP264.PROD.OUTLOOK.COM 2025-09-11T06:13:26.046Z 08DDF01279F3FE5F])

   ----- Transcript of session follows -----
... while talking to tarkett-com.mail.protection.outlook.com.:
>>> DATA
<<< 550 5.4.1 Recipient address rejected: Access denied. For more information see https://aka.ms/EXOSmtpErrors [MR1PEPF00000D5A.FRAP264.PROD.OUTLOOK.COM 2025-09-11T06:13:26.046Z 08DDF01279F3FE5F]
550 5.1.1 <[email-masked]>... User unknown
<<< 503 5.5.2 Need rcpt command [MR1PEPF00000D5A.FRAP264.PROD.OUTLOOK.COM 2025-09-11T06:13:26.046Z 08DDF01279F3FE5F]