# Custom SMTP

> Connect any SMTP server to BooleanSMTP with host, port, encryption and authentication, then send a test email.

**Custom SMTP** connects BooleanSMTP to any SMTP server — your host's own mail server, a provider
not listed elsewhere in Mailers, or an SMTP relay a provider issues you directly.

## Before you begin

From your SMTP provider or host: a **host**, a **port**, whether it needs **encryption**, and — if
it requires authentication — a **username** and **password**.

## Add the connection

<Steps>

1. In your WordPress admin sidebar, go to **BooleanSMTP → Mailers**.
2. Click **Add Connection** and choose **Custom SMTP**.
3. Under **Sender Settings**, fill in **From Email** and **From Name**.
4. Under **SMTP Server Credentials**, fill in **SMTP Host**, **Port** (default `587`), and
   **Encryption Method** — **None**, **SSL**, or **TLS** (default **TLS**).
5. Turn on **Authentication** if your server requires a login, then fill in **SMTP Username** and
   **Password**.
6. Choose **Credential Storage**: **Database**, **WP Config**, or **Environment**. To keep keys out
   of the database, see [Storing credentials in wp-config](/sending/wp-config-credentials/).
7. Click **Register Connection**.

</Steps>

![The Custom SMTP connection form, with Host, Port, Encryption Method, Auto TLS and Authentication fields.](../../../assets/screenshots/custom-smtp.webp)

### Advanced fields

- **Auto TLS (STARTTLS)** — on by default.
- **Connection Timeout (seconds)** — 1–300, default 10.
- **SMTP Debug Level** — **Off**, **Errors Only**, **Commands**, **Connection + Commands**, or
  **Low-level + Full Trace**; captures the raw SMTP conversation while troubleshooting.
- **Client Hostname (EHLO/HELO)** — override the hostname your server announces.
- **Verify TLS Peer Certificate** — on by default; turn off only for a server with a self-signed
  certificate you trust.
- **Enable SMTP Keep-Alive** — off by default; keeps the connection open across a batch of sends.

## Send a test email

Use **Test Email** in the sidebar to confirm the connection works — see
[Send a test email](/getting-started/send-a-test-email/) for the steps.

## Common errors

- **"Connection timeout" or "Network error"** — check your firewall allows outbound SMTP, try the
  other common port (465 for SSL, 587 for TLS), and check with your host for port restrictions.
- **"Authentication failed"** — verify the username and password are correct; some providers require
  an app password rather than your normal account password.
- Turn on **SMTP Debug Level** and re-send to capture the raw SMTP conversation for the failed
  attempt in **Email Logs**.

## Next steps

- [Send a test email](/getting-started/send-a-test-email/)
- [Set a fallback connection](/sending/fallback-and-retries/)
- [Check delivery in Logs](/logs/)
- [Nothing arrived?](/learn/nothing-arrived/)