Other SMTP

Other SMTP (Custom)

Connect to any SMTP server not in the preset list — your hosting provider's mail server, a self-hosted Postfix, an internal relay, etc.

Easy~3 minSMTP

When to use Other SMTP

• Your web host provides an SMTP server (e.g. cPanel mail).
• You run your own mail server (Postfix / Exim / Postal / etc).
• You use a provider not in the preset list.

For any preset-supported provider (Gmail, SendGrid, Mailgun…), use the dedicated guide instead — those have validated host/port/encryption combinations.

Common port + encryption combinations

Port	Encryption	When to use
25	None	Unencrypted relay. Often blocked by ISPs and hosts. Don't use unless internal.
465	SSL	Implicit TLS. Legacy but still common. Some servers prefer this.
587	TLS	STARTTLS. Recommended. Modern standard.
2525	TLS	Same as 587, alternative for ISP-blocked port 587.

Step-by-step

Get SMTP credentials from your provider

You need: host, port, encryption, username, password.

Common sources:

• Your hosting control panel (cPanel → Email Accounts → Configure email client → SMTP settings).
• Your provider's documentation page.
• Your sysadmin / IT team for self-hosted servers.

Add the connection in SendGrail

SendGrail → Connections → Add Connection → pick Other SMTP (at the bottom of the provider grid).

Fill in:

• Connection Name: descriptive (e.g. "cPanel Mail" or "Internal Postfix")
• From Email: an address your SMTP server allows you to send as
• From Name: display name
• Host: SMTP server hostname
• Port: typically 587 (TLS) or 465 (SSL)
• Encryption: TLS / SSL / None
• Username: SMTP username (usually full email address)
• Password: SMTP password
• Authentication: ON (almost always required)
• Auto TLS: ON (auto-upgrade to TLS when server advertises support)
• Return-Path: ON (set bounce-back address to your From Email)

Click Save.

Test

SendGrail → Test Email → pick the new connection → send to yourself.

If it fails, check the email log row for the SMTP error and consult Troubleshooting below.

Troubleshooting

Could not connect to host

Server hostname is wrong, or your WordPress server's outbound port is blocked. Try a different port (587, 465, 2525) — some hosts block specific ones. Verify the hostname with ping or telnet your.smtp.host 587.

535 Authentication failed

Username or password is wrong. For most servers, the username is the full email address, not just the part before @. Double-check.

554 Relay access denied

The SMTP server doesn't trust the sending IP. Either:

• Your WP server's IP isn't in the SMTP server's allowed-relay list — ask the SMTP admin to whitelist it.
• The From Email's domain isn't permitted by this SMTP relay — try a different sender address.

TLS / SSL errors

• Try the Auto TLS toggle off.
• Verify you picked the right encryption for the port (587=TLS, 465=SSL, almost never None).
• Some SMTP servers have outdated TLS versions; ask the admin for current cipher info.

Slow sending / timeouts

• Increase Connection Timeout in Settings → Advanced → Connection Timeout (default 30s, max 120s).
• Some hosts (especially shared) throttle outbound SMTP.

What's next

• Settings → Fallback — set this as the fallback for your primary connection so it activates only when the primary fails.
• Failure Alerts — get pinged in Slack/Telegram on SMTP errors.