# Send email with SMTP

Use Prontuno SMTP credentials with any application, framework, or service that supports authenticated SMTP.

## Connection settings

- Host | `smtp.prontuno.net`
- Recommended port | `587` with STARTTLS
- Other supported ports | `25`, `465`, and `2525`
- Authentication | Required
- Username | The SMTP Username generated by Prontuno
- Password | The SMTP Password generated by Prontuno
- Encryption | SSL/TLS or STARTTLS

Use port `587` with STARTTLS when your application supports it. Port `2525` is a useful alternative when a hosting provider blocks standard SMTP ports.

## Create an SMTP credential

1. [Verify a sending domain.](#)
2. Open **SMTP Credentials** in Prontuno.
3. Select **New SMTP Credential**.
4. Give it a descriptive name, such as `Production web app`.
5. Choose the verified domain and confirm with your account password.
6. Copy the generated username and password.

### Copy the password now

The password is displayed only when it is created or reset. If it is lost, reset the credential and update every application that uses it.

## Example environment configuration

Use the variable names expected by your framework or mail library. A common configuration looks like this:

```
MAIL_MAILER=smtp
MAIL_HOST=smtp.prontuno.net
MAIL_PORT=587
MAIL_USERNAME=YOUR_PRONTUNO_SMTP_USERNAME
MAIL_PASSWORD=YOUR_PRONTUNO_SMTP_PASSWORD
MAIL_ENCRYPTION=tls
MAIL_FROM_ADDRESS=notifications@example.com
MAIL_FROM_NAME="Example App"
```

Do not commit the real username or password to your repository.

## Message requirements

- The `From` address must use the verified domain attached to the SMTP credential.
- Use a real address that identifies your application or service.
- Send only transactional messages related to a user’s action, account, purchase, or service.
- Use a valid recipient address and a non-empty subject.
- Keep one credential per application or environment so it can be rotated independently.

## Test the connection

1. Send a test message to an inbox you control.
2. Open **Emails** in Prontuno.
3. Search for the subject or recipient.
4. Open the message to inspect its status and event timestamps.

The **Last Used** value on the SMTP Credentials page updates after a successful login and can help confirm which credential an application is using.

## Common SMTP errors

- Problem | What to check
- Connection timeout | Confirm the host and port. Try port 587 or 2525 and check whether your host blocks outbound SMTP.
- TLS or certificate error | Enable STARTTLS on port 587, update the server’s certificate store, and do not disable certificate verification.
- Authentication failed | Use the generated SMTP username, not your Prontuno login email. Reset the credential if the password is unknown.
- Sender rejected | Make sure the `From` address uses the verified domain bound to this credential.
- Credential disabled | Check its status in Prontuno and confirm that sending is enabled for the domain and team.

## Next steps

For delivery issues, see [Troubleshoot sending and delivery](#).