Free tools
Bounce code lookup
Enter a bounce code from MailFleet logs or provider webhooks (e.g. 550, 5.1.1, 4.7.1).
What this checks
Maps numeric SMTP codes and enhanced status codes to human-readable causes and remediation steps.
Why it matters
Understanding bounces helps maintain list hygiene and fix provider configuration issues.
Results
Common issues
- Treating soft bounces like hard bounces or vice versa.
- Retrying repeatedly to addresses with permanent 5.x.x failures.
- Ignoring enhanced status codes (e.g. 5.1.1) inside SMTP replies.
How to fix
- Suppress hard-bounced addresses from future campaigns.
- Investigate soft bounces after multiple failures before removal.
- Cross-reference codes with provider documentation and MailFleet logs.
How MailFleet helps
MailFleet campaign logs and reports surface bounce codes with provider context for faster list hygiene decisions.
Related free tools
Delivery note: MailFleet helps users manage campaigns through their own sending providers. Delivery outcomes depend on sender reputation, DNS authentication, content quality, recipient engagement, list quality, provider rules, and mailbox filtering systems.
For regulatory context on commercial email in the United States, see the FTC CAN-SPAM compliance guide.
Frequently asked questions
Hard bounces are permanent failures (bad address). Soft bounces are temporary (mailbox full, greylisting). Handle each differently.
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