Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Thu, 4 Sep 2025 08:17:53 +0200

The original message was received at Thu, 4 Sep 2025 08:17:52 +0200
from m0220690.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 [AM4PEPF00025F9B.EURPRD83.prod.outlook.com 2025-09-04T06:17:53.284Z 08DDE7CAD29E073D])

   ----- Transcript of session follows -----
... while talking to storebrand.mail.protection.outlook.com.:
>>> DATA
<<< 550 5.4.1 Recipient address rejected: Access denied. For more information see https://aka.ms/EXOSmtpErrors [AM4PEPF00025F9B.EURPRD83.prod.outlook.com 2025-09-04T06:17:53.284Z 08DDE7CAD29E073D]
550 5.1.1 <[email-masked]>... User unknown
<<< 503 5.5.2 Need rcpt command [AM4PEPF00025F9B.EURPRD83.prod.outlook.com 2025-09-04T06:17:53.284Z 08DDE7CAD29E073D]