Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Tue, 13 Jan 2026 09:03:39 +0200

The original message was received at Tue, 13 Jan 2026 09:03:26 +0200
from gate.edelkey.net [213.138.147.140]

   ----- 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 [DB5PEPF00014B8B.eurprd02.prod.outlook.com 2026-01-13T07:03:39.429Z 08DE526960375ACF])

   ----- Transcript of session follows -----
... while talking to halton-com.mail.protection.outlook.com.:
>>> DATA
<<< 550 5.4.1 Recipient address rejected: Access denied. For more information see https://aka.ms/EXOSmtpErrors [DB5PEPF00014B8B.eurprd02.prod.outlook.com 2026-01-13T07:03:39.429Z 08DE526960375ACF]
550 5.1.1 <[email-masked]>... User unknown
<<< 503 5.5.2 Need rcpt command [DB5PEPF00014B8B.eurprd02.prod.outlook.com 2026-01-13T07:03:39.429Z 08DE526960375ACF]