SMTP code 550 DY-002
What the knowledge base's own tables say about this code, and which articles say it — a description of the reply, never a placement prediction.
This line comes from a knowledge base article on Microsoft, not on the standard.
- Meaning
- Sending pattern suggests a compromised or virus-infected host
- Next step
- Clean the host; contact ISP
From Microsoft Outlook.com Sender Requirements · SMTP error codes