# Postmark error 406: you tried to send to a recipient that has been marked as inactive

> A 406 means Postmark deactivated the address after a hard bounce, complaint or manual block. Do not retry it. Surface it, and reactivate only on the owner's request.

A user says "I never got my sign-in link". Your logs show:

```
422 Unprocessable Entity
ErrorCode: 406
Message: You tried to send to recipient(s) that have been marked as inactive.
```

## What it means

Postmark keeps a suppression list per message stream. An address lands on it after:

- a **hard bounce** (the mailbox does not exist),
- a **spam complaint** (the person clicked "report spam"),
- a **manual suppression** (you, support, or an unsubscribe on a broadcast stream).

After that, Postmark refuses every send to that address on that stream. It does this to protect your reputation. The message was never sent.

## What not to do

- **Do not retry.** It is a 422. It fails the same way every time.
- **Do not reactivate it to make the error go away.** A dead mailbox bounces again. A complainer complains again, and complaints cost more than bounces.
- **Do not switch streams to get around it.** Sending a login link on the broadcast stream "because it's not blocked there" puts transactional mail on marketing infrastructure with an unsubscribe footer.

## What to do

1. **Turn it into a clear domain error.** The Node SDK throws `Errors.InactiveRecipientsError` for this case. Catch it at the send boundary and throw your own `EmailSuppressedError(address)`.
2. **Show the user something useful.** "We can't deliver email to this address. Check it, or use a different one." Not "something went wrong".
3. **Find out why.** Search the address in Postmark (**Suppressions** tab on the stream), or query the API:

```ts
const { Suppressions } = await client.getSuppressions("outbound", { emailAddress });
// [{ EmailAddress, SuppressionReason: "HardBounce" | "SpamComplaint" | "ManualSuppression", Origin, CreatedAt }]
```

4. **Reactivate only on request.** If the owner fixed their mailbox and asks, delete the suppression:

```ts
await client.deleteSuppressions("outbound", { Suppressions: [{ EmailAddress: emailAddress }] });
```

`SpamComplaint` suppressions cannot be deleted through the API. The person reported you, so they have to write to you (or to Postmark support) to undo it.

## Refuse before you call

A 406 costs an API round trip and happens after you rendered the email. Keep a local copy of the list, filled by the Bounce, SpamComplaint and SubscriptionChange webhooks, and check it first. Treat the local list as a fast path, not the authority:

- If the local check fails (database down), let the send through. Postmark still refuses with a 406.
- If Postmark reactivates an address (a SubscriptionChange with `SuppressSending: false`), remove it locally too.

## Checklist

- [ ] `InactiveRecipientsError` is mapped to a domain error, not reported as a crash.
- [ ] No retry on any 422.
- [ ] Users see an actionable message.
- [ ] Reactivation is a support action on request, never automatic.

---

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