SMTP code 421 RP-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
- Rate limit exceeded on this connection (reputation)
- Next step
- Same as RP-001
- 421 RP-001, in the same table
- Improve reputation; slow down; escalate via sender support
From Microsoft Outlook.com Sender Requirements · SMTP error codes