# Other SMTP

Source: https://catalystgroup.gg/docs/email-delivery/mailer-other-smtp/
Updated: 2026-10-19 · By Duane Garner

Send WordPress email through any SMTP server: host, encryption, port, Auto TLS, authentication and common server settings.

This guide explains how to send your site's email through any SMTP server, such as your web host's mail server, a business mailbox, or a sending service's SMTP relay. Use it when your provider has no dedicated mailer in CRM-NG SMTP, or when your host blocks outgoing API calls but allows SMTP.

 

**Other SMTP** works with almost any mail server, but it is the least robust choice. It relies on a stored password, many servers limit how much you may send, and some hosts block SMTP ports. If your provider has its own mailer in CRM-NG SMTP, prefer that one. See [Choosing a mail service](https://catalystgroup.gg/docs/email-delivery/choose-a-mailer/).

 

## Before you start

 

Get these details from your mail provider:

 
- The SMTP server name (host).
- The port and the type of encryption it expects.
- The username and password (or app password, or SMTP key) for sending.
- The address you are allowed to send from. Most servers only accept mail from the account's own address or its aliases.

 

## Step 1: Enter the server details

 
1. Choose the mailer
  In WordPress, open **CRM-NG SMTP → Settings → General** and set **Mailer** to **Other SMTP**.
2. Enter the host
  Type the server name into **SMTP Host**, for example `smtp.yourprovider.com`. Do not add `https://` or a port.
3. Choose the encryption
  Under **Encryption**, pick **TLS**, **SSL** or **None** to match your provider (see the table below).
4. Enter the port
  Type the port into **SMTP Port**. It must match the encryption.
5. Leave Auto TLS on
  Keep **Auto TLS** switched on unless you have a reason to change it (see below).

 

### Encryption and port

 

| Encryption | Port | What happens |
| --- | --- | --- |
| TLS | 587 | The connection starts plain and switches to encryption straight away (STARTTLS). Recommended for most servers. |
| SSL | 465 | The connection is encrypted from the first moment (also called implicit TLS). Use it when your provider asks for 465. |
| None | 25 or 587 | No encryption is requested. Only for servers inside a trusted network. Port 25 is blocked by many hosts. |

 

If your provider offers both SSL and TLS, pick **TLS** on port 587.

 

### Auto TLS

 

**Auto TLS** matters when **Encryption** is **None**; the switch is greyed out with **TLS**, which already encrypts. With **None**, it upgrades the connection to encryption whenever the server offers it. Leave it on. Turn it off only if a misconfigured server advertises encryption but then fails, for example with a certificate error on a local relay.

 

## Auth type

 

Almost every SMTP server asks the site to sign in before it accepts mail.

 
1. Turn on Authentication
  Switch **Authentication** on. The username and password fields appear.
2. Enter the username
  Type your sign-in name into **SMTP Username**. It is usually your full email address; some services use a special login (for example Brevo's SMTP login, or `apikey` for SendGrid).
3. Enter the password
  Type the password into **SMTP Password**. For Gmail, Yahoo, iCloud and Zoho this must be an app password, not your normal password. For sending services it is usually an SMTP key.
4. Save
  Press **Save Settings**.

 

CRM-NG SMTP signs in with whichever method the server offers (normally LOGIN or PLAIN over an encrypted connection). If your server wants something else, such as OAuth only, use that provider's own mailer instead.

 

The password is stored encrypted in your database. To keep it out of the database entirely, define it in `wp-config.php` with `CRMNG_SMTP_SMTP_PASS`; the field is then locked. See [Securing settings with wp-config constants](https://catalystgroup.gg/docs/email-delivery/secure-settings-constants/). Use **Remove Password** to clear a stored password.

 

Leave **Authentication** off only for servers that accept mail without signing in, such as a relay on your own network that trusts your server's IP address.

 

## Step 2: Set the sender

 
1. Set the From Email
  Set **From Email** to the address your SMTP account may send from.
2. Force it
  Tick **Force From Email** so other plugins cannot use an address the server will refuse. Set **From Name** too.
3. Keep bounces
  Tick **Return Path** so bounce messages come back to the From Email.
4. Save
  Press **Save Settings**.

 

## Common SMTP settings

 

These are typical values. Always check your provider's own help pages, as they can change.

 

| Provider | SMTP Host | Encryption / Port | Notes |
| --- | --- | --- | --- |
| Your web host | often mail.yourdomain.com | TLS 587 or SSL 465 | Ask your host for exact values. |
| Gmail | smtp.gmail.com | TLS 587 | Needs an app password; the Gmail mailer is better. |
| Microsoft 365 | smtp.office365.com | TLS 587 | Often switched off by admins; the Microsoft 365 mailer is better. |
| Yahoo Mail | smtp.mail.yahoo.com | SSL 465 | Needs an app password. |
| iCloud Mail | smtp.mail.me.com | TLS 587 | Needs an app-specific password. |
| Zoho Mail | smtp.zoho.com (by region) | TLS 587 | The Zoho mailer fills this in. |
| Brevo relay | smtp-relay.brevo.com | TLS 587 | Login and SMTP key from Brevo, see Brevo. |
| SendGrid relay | smtp.sendgrid.net | TLS 587 | Username apikey, password is the API key. |
| Amazon SES | email-smtp.<region>.amazonaws.com | TLS 587 | Uses SES SMTP credentials, not IAM keys. |

 

## Send a test email

 

Open **CRM-NG SMTP → Tools → Email Test**, enter your address in **Send To**, and press **Send Email**. If it fails, the error banner shows the server's reply. Turning on **Debug Email Sending** under **Tools → Debug Events** records the whole conversation with the server. See [Sending a test email](https://catalystgroup.gg/docs/email-delivery/send-a-test-email/) and [Debug events](https://catalystgroup.gg/docs/email-delivery/debug-events/).

 

## Troubleshooting

 
- The server refuses your username or password: [535 Authentication failed](https://catalystgroup.gg/docs/email-delivery/error-535-authentication-failed/)
- The server wants an app password: [534: application-specific password required](https://catalystgroup.gg/docs/email-delivery/error-534-app-password-required/)
- No connection to the server: [Could not connect to SMTP host](https://catalystgroup.gg/docs/email-delivery/error-could-not-connect-to-smtp-host/), [Connection refused](https://catalystgroup.gg/docs/email-delivery/error-connection-refused/), [Connection timed out](https://catalystgroup.gg/docs/email-delivery/error-connection-timed-out/)
- The host name is wrong: [Hostname could not be resolved](https://catalystgroup.gg/docs/email-delivery/error-hostname-could-not-be-resolved/)
- Certificate problems: [SSL certificate verify failed](https://catalystgroup.gg/docs/email-delivery/error-ssl-certificate-verify-failed/)
- The server refuses the sender: [553 Sender address rejected](https://catalystgroup.gg/docs/email-delivery/error-553-sender-address-rejected/)
- The server refuses the recipient: [550 Requested action not taken](https://catalystgroup.gg/docs/email-delivery/error-550-recipient-rejected/)
- Limits and temporary problems: [421 Connection timeout](https://catalystgroup.gg/docs/email-delivery/error-421-connection-timeout/), [451 Temporary local problem](https://catalystgroup.gg/docs/email-delivery/error-451-temporary-server-problem/), [554 Transaction failed](https://catalystgroup.gg/docs/email-delivery/error-554-transaction-failed/)
- Mail arrives in spam: [Emails landing in spam](https://catalystgroup.gg/docs/email-delivery/emails-landing-in-spam/) and [Adding DNS records](https://catalystgroup.gg/docs/email-delivery/dns-records/)

 

## Related

 
- [Choosing a mail service](https://catalystgroup.gg/docs/email-delivery/choose-a-mailer/)
- [Backup SMTP transport](https://catalystgroup.gg/docs/email-delivery/backup-smtp-transport/)
- [Securing settings with wp-config constants](https://catalystgroup.gg/docs/email-delivery/secure-settings-constants/)
- [Sender name, address and the Force settings](https://catalystgroup.gg/docs/email-delivery/sender-name-and-address/)
- [Troubleshooting email delivery](https://catalystgroup.gg/docs/email-delivery/troubleshooting/)