SMTP code 553 5.7.1
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.
- Provider
- Yahoo
- Response matched (regex, abridged)
- 553 5.7.1 [BL (IP listed by Spamhaus)
- Trigger
- 5/hr
- Action
- Suspend
- Duration
- 2 h
From Per-Provider Tuning Baselines · Automated-throttle rules per provider (community-contributed)