Understanding Bounces
Learn the difference between soft and hard bounces
Understanding Bounces
A bounce occurs when an email you send cannot be delivered to the recipient's mailbox. Understanding the different types of bounces and how Mailnaptic handles them is essential for maintaining a clean list and strong sender reputation.
Hard bounces
A hard bounce is a permanent delivery failure. The email address is invalid, the domain does not exist, or the receiving server has explicitly rejected the message with a permanent error code. Common reasons include:
- The email address does not exist (typo, deleted account).
- The domain name is invalid or has no mail server.
- The receiving server has permanently blocked your sending address.
How Mailnaptic handles hard bounces
When a hard bounce is detected, Mailnaptic automatically suppresses the contact. This means the contact's status is updated so they will not receive any future emails. This is critical because repeatedly sending to invalid addresses damages your sender reputation.
Suppressed contacts remain in your contact list for record-keeping, but they are excluded from all future campaign sends and automation emails.
Soft bounces
A soft bounce is a temporary delivery failure. The email address is valid, but the message could not be delivered right now. Common reasons include:
- The recipient's mailbox is full.
- The receiving server is temporarily unavailable or overloaded.
- The message is too large for the recipient's mail server.
- The receiving server is applying temporary rate limits to your sending IP.
How Mailnaptic handles soft bounces
Soft bounces are retried automatically. Mailnaptic's sender worker will attempt to deliver the message again after a delay. If the message continues to soft bounce after multiple attempts, it is recorded as a final soft bounce for that campaign, but the contact is not suppressed.
However, if a contact consistently soft bounces across multiple campaigns, you should consider removing them from your list manually, as persistent soft bounces can indicate an abandoned or problematic address.
Viewing bounce data
Campaign level
- Open a sent campaign from the Campaigns list.
- The campaign detail page shows bounce counts in the statistics summary.
- Check the Activity tab to see individual bounce events, including the bounce type and the error message returned by the receiving server.
Organization level
- Navigate to Organization Settings > Deliverability.
- The deliverability dashboard shows aggregate bounce rates across all your campaigns.
- The ISP Stats breakdown shows which mailbox providers are generating the most bounces.
Acceptable bounce rates
| Bounce rate | Status | Action |
|---|---|---|
| Under 2% | Healthy | No action needed |
| 2% - 5% | Warning | Review list hygiene, remove old addresses |
| Above 5% | Critical | Pause sending, clean your list immediately |
Reducing your bounce rate
- Use double opt-in — Confirms that the email address is valid and owned by the subscriber.
- Clean your list regularly — Remove contacts who have not engaged in 6+ months.
- Validate on import — Check for obvious formatting errors (missing @ symbol, invalid domains) before importing contacts.
- Remove role-based addresses — Addresses like info@, admin@, and support@ often bounce or generate complaints.
- Monitor after every send — Check bounce rates after each campaign and investigate any sudden increases.
Keeping your bounce rate low signals to mailbox providers that you maintain a clean, permission-based list, which directly improves your inbox placement.