Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Thu, 1 Jan 2026 13:43:55 +0100

The original message was received at Thu, 1 Jan 2026 13:43:55 +0100
from m0417416.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 [AM1PEPF000252DE.eurprd07.prod.outlook.com 2026-01-01T12:43:55.569Z 08DE48EC931E4CBF])

   ----- Transcript of session follows -----
... while talking to brenntagnordic-com02b.mail.protection.outlook.com.:
>>> DATA
<<< 550 5.4.1 Recipient address rejected: Access denied. For more information see https://aka.ms/EXOSmtpErrors [AM1PEPF000252DE.eurprd07.prod.outlook.com 2026-01-01T12:43:55.569Z 08DE48EC931E4CBF]
550 5.1.1 <[email-masked]>... User unknown
<<< 503 5.5.2 Need rcpt command [AM1PEPF000252DE.eurprd07.prod.outlook.com 2026-01-01T12:43:55.569Z 08DE48EC931E4CBF]