# Why is an address on my suppression list?

> MailBlastr auto-adds an address to your account-wide suppression list on a hard bounce, a complaint, or an unsubscribe — and skips it on every later send to protect your reputation.

Your **suppression list** is the set of addresses MailBlastr will not send to. It's how the platform stops you from repeatedly mailing addresses that are permanently broken or that have asked you to stop — both of which damage your sender reputation and can violate anti-spam law.

## How an address gets suppressed

MailBlastr adds an address automatically in three cases:

- **Hard bounce** — the receiving server reports a *permanent* bounce (the mailbox doesn't exist, the domain is invalid, or the recipient's server permanently rejected the message). Soft/temporary bounces do **not** suppress, because the problem is expected to clear up.
- **Complaint** — the recipient marked your message as spam (a feedback-loop complaint). Complaints always suppress.
- **Unsubscribe** — a recipient opted out via a campaign unsubscribe link or one-click `List-Unsubscribe`, or you suppressed them manually.

> **Note:** Suppression is **account-wide**: once an address is suppressed, it's skipped across all of your sends — transactional `POST /emails`, batches, and campaigns alike. It only affects *your* account; another account's suppressions never touch yours, and yours never touch theirs.

## What happens on a send

On **every send path**, MailBlastr checks each recipient against your suppression list before handing the message off for delivery. Suppressed recipients are skipped — the rest of the send proceeds normally. For a single `POST /emails`, a suppressed recipient is recorded with a `suppressed` status rather than being mailed. See [Email suppressions](https://www.mailblastr.com/docs/emails/suppressions).

## Should you remove an address?

Usually **no** — suppression is protecting you. But the right action depends on why the address was suppressed:

| Reason | What to do |
| --- | --- |
| Hard bounce | Leave it. The mailbox is gone; re-sending only produces more bounces and hurts reputation. Fix the source of bad addresses instead. |
| Complaint | Leave it. The recipient explicitly flagged your mail as unwanted — re-mailing risks legal exposure and more complaints. |
| Unsubscribe | Leave it unless the person genuinely re-subscribes through a new, documented opt-in. |

> **Warning:** If you remove a suppression and re-add the address, you take on the risk: a previously-complained or invalid recipient who bounces or complains again will hurt your standing with mailbox providers. Only do this when you have fresh, explicit [consent](https://www.mailblastr.com/docs/kb/consent).

## Keeping the list from growing

A growing suppression list is a symptom — usually of a list that wasn't cleanly opted-in or has gone stale. Tighten consent at signup and practice ongoing [audience hygiene](https://www.mailblastr.com/docs/kb/audience-hygiene).