421 4.7.0
421 4.7.0 Temporary System Problem
Gmail encountered a temporary server issue and asked you to try again later.
421 4.7.0 is usually an infrastructure blip on Google’s side. Respect the retry window or Gmail may extend the deferral.
Severity
WARNING
Provider
Gmail
Reference
Mitigation Portal
Last Reviewed
2025-06-01
How to Fix 421 4.7.0
Follow these steps to resolve this Gmail SMTP error and restore normal delivery.
- ✓Implement exponential backoff when retrying the delivery.
- ✓Avoid hammering the same connection with rapid-fire retries.
- ✓Monitor for patterns that might indicate a broader Google outage.
- ✓Keep the incident timeline for postmortems with stakeholders.
Helpful Resources
More Gmail SMTP Codes
Keep these related troubleshooting guides handy while addressing 421 4.7.0.
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