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Unable to connect to outgoing SMTP email server
This guide explains the three most common reasons you cannot connect to an outgoing SMTP server: your ISP blocking ports, incorrect settings in your email client, and outbound SMTP restrictions when connecting from your hosting account to a third-party service.
There are three distinct situations that can cause an "unable to connect to outgoing SMTP server" error. This guide covers each one separately so you can go straight to the scenario that applies to you.
- Your ISP is blocking outgoing SMTP ports
- You cannot send email from your email client
- Your website or application cannot connect to a third-party SMTP service
Your ISP is blocking outgoing SMTP ports
Some Internet Service Providers (ISPs) block outgoing connections on certain ports - most commonly port 25 - to reduce spam. If your ISP does this, your email client may show an error such as "Unable to connect to your outgoing SMTP email server" even when your settings are otherwise correct.
The most reliable fix is to switch to a secure, authenticated port. We support ports 465 (SSL/TLS) and 587 (STARTTLS) for outbound SMTP, and ISPs rarely block these. See the section below for how to update your email client.
If you have already tried both of those ports and still cannot connect, the block may be at the network level rather than the port level. In that case, contact your ISP directly and ask whether outgoing SMTP connections are restricted on your connection.
You cannot send email from your email client
We no longer allow connections on port 25. All outbound SMTP must use a secure, authenticated port.
Ports we support
| Protocol | Port | Security |
|---|---|---|
| SMTP (submission) | 465 | SSL/TLS |
| SMTP (submission) | 587 | STARTTLS |
Make sure SMTP authentication is enabled in your email client. This is required when using either of the ports above.
If you are unsure which server address to use, you can find your full mail server configuration details in cPanel. See Finding the Email Client Configuration Details in cPanel for guidance.
Updating your email client settings
- Open your email client's account settings.
- Navigate to the advanced or server settings section.
- Find the outgoing (SMTP) port.
- Change it to 465 (SSL/TLS) or 587 (STARTTLS).
- Ensure SMTP authentication is enabled.
- Save the settings and try sending an email again.
For step-by-step instructions for specific clients, see Updating existing email connections to use SSL.
Your website or application cannot connect to a third-party SMTP service
This scenario is different from the two above. Here, the connection attempt is not coming from your computer - it is coming from your hosting account. For example, your WordPress site or a custom application may be trying to relay mail through an external SMTP service such as SendGrid or Mailgun.
Outbound SMTP connections from our servers to external mail services are disabled by default. This is a server-level restriction, not something you can change yourself from within cPanel.
To request that we open the relevant ports, please contact our support team and include the following information:
- The name of the third-party SMTP service you plan to connect to
- The port or ports you need to connect on
We review each request individually and will open the ports on a case-by-case basis.
Still having trouble?
If you are still unable to send email after following the steps above, please contact our support team.