> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mailofly.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Delivery statuses

# Delivery Statuses

Every email processed by Mailofly progresses through distinct lifecycle states:

***

## Status Definitions

| Status         | Meaning                                                                                  | Next Possible States        |
| :------------- | :--------------------------------------------------------------------------------------- | :-------------------------- |
| **Queued**     | Message accepted by the API and enqueued in our delivery pipeline.                       | Sent, Failed, Cancelled     |
| **Sent**       | Message handed off to the recipient's mail server via SMTP.                              | Delivered, Bounced, Failed  |
| **Delivered**  | The recipient's mail server acknowledged acceptance (`250 2.0.0 OK`).                    | Opened, Clicked, Complained |
| **Opened**     | The recipient opened the email and downloaded the tracking pixel.                        | Clicked                     |
| **Clicked**    | The recipient clicked at least one link inside the email.                                | -                           |
| **Bounced**    | The recipient's server rejected delivery (e.g. mailbox does not exist).                  | -                           |
| **Complained** | The recipient flagged the message as spam / abuse via their email provider.              | -                           |
| **Failed**     | Message could not be processed due to bad credentials, policy limits, or malformed data. | -                           |
| **Cancelled**  | A scheduled email was cancelled prior to dispatch.                                       | -                           |

***

## SMTP Diagnostic Codes

When an email bounces or fails, Mailofly captures the exact SMTP error code returned by the receiving MTA:

* `550 5.1.1 User unknown`: The mailbox does not exist.
* `452 4.2.2 Mailbox full`: Temporary soft bounce.
* `554 5.7.1 Relay access denied / SPF fail`: Authentication policy rejection.


## Related topics

- [CLI](/cli/index.md)
- [Introduction](/logs/introduction.md)
- [Manage Emails](/sending/manage-emails.md)
- [Filtering and troubleshooting](/logs/filtering-and-troubleshooting.md)
- [Regions](/domains/regions.md)