


| Status | What it means | Action |
|---|---|---|
| Valid | Mailbox exists and accepts email | Keep - safe to send |
| Invalid | Mailbox doesn't exist or is permanently blocked | Suppress immediately |
| Catch-all | Domain accepts all email individual mailbox uncertain | Check Safe-to-Send flag |
| Unknown | Mail server didn't respond at verification time | Exclude from current send; re-verify later |
| Safe-to send | What it means | Action |
|---|---|---|
| Yes | Address is verified safe | Send |
| Risky | Uncertainty present: catch-all, unusual SMTP response | Exclude from large or cold sends |
| No | Invalid - do not send | Suppress |
| Unknown | Status cannot be determined | Exclude from current campaign |

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