Subject: Returned mail: see transcript for details

From: Mail Delivery Subsystem <[email-masked]>
Date: Thu, 16 Oct 2025 08:47:31 GMT

The original message was received at Thu, 16 Oct 2025 08:47:30 GMT
from m0341352.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 [BL02EPF0001A0FC.namprd03.prod.outlook.com 2025-10-16T08:47:31.546Z 08DE09B568265254])

   ----- Transcript of session follows -----
... while talking to danaher.mail.protection.outlook.com.:
>>> DATA
<<< 550 5.4.1 Recipient address rejected: Access denied. For more information see https://aka.ms/EXOSmtpErrors [BL02EPF0001A0FC.namprd03.prod.outlook.com 2025-10-16T08:47:31.546Z 08DE09B568265254]
550 5.1.1 <[email-masked]>... User unknown
<<< 503 5.5.2 Need rcpt command [BL02EPF0001A0FC.namprd03.prod.outlook.com 2025-10-16T08:47:31.546Z 08DE09B568265254]