421 4.7.0 [TS03]
TS03 Reputation Hold
Traffic is temporarily held while Yahoo reviews a potential abuse signal.
TS03 is triggered by spikes in unknown users, sudden content changes, or infrastructure anomalies that resemble abuse.
Severity
WARNING
Provider
Yahoo Mail
Reference
TS03
Last Reviewed
2025-06-01
How to Fix 421 4.7.0 [TS03]
Follow these steps to resolve this Yahoo Mail SMTP error and restore normal delivery.
- ✓Audit recent creative, link domains, and sending speeds for big shifts.
- ✓Ensure bounce processing removes invalid Yahoo addresses immediately.
- ✓Confirm no other teams or systems are sending through the same IPs.
- ✓Resume at a slower pace after the issue is corrected.
Helpful Resources
More Yahoo Mail SMTP Codes
Keep these related troubleshooting guides handy while addressing 421 4.7.0 [TS03].
Still experiencing Yahoo Mail delivery issues?
Run your domain through our free deliverability tools or book a session with Bento's deliverability specialists.