Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Tue, 13 Jan 2026 07:03:20 GMT

The original message was received at Tue, 13 Jan 2026 07:03:20 GMT
from m0223511.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 [AMS1EPF00000048.eurprd04.prod.outlook.com 2026-01-13T07:03:20.402Z 08DE4E5FA65673EC])

   ----- Transcript of session follows -----
... while talking to nibe-com.mail.protection.outlook.com.:
>>> DATA
<<< 550 5.4.1 Recipient address rejected: Access denied. For more information see https://aka.ms/EXOSmtpErrors [AMS1EPF00000048.eurprd04.prod.outlook.com 2026-01-13T07:03:20.402Z 08DE4E5FA65673EC]
550 5.1.1 <[email-masked]>... User unknown
<<< 503 5.5.2 Need rcpt command [AMS1EPF00000048.eurprd04.prod.outlook.com 2026-01-13T07:03:20.402Z 08DE4E5FA65673EC]