Configure Custom External SMTP Email Provider
Auth0 allows you to configure your own SMTP email provider so you can more completely manage, monitor, and troubleshoot your email communications. Auth0's built-in email infrastructure should be used for testing emails only.
When setting up a custom SMTP provider, Auth0 supports Basic Auth. Although as of October 1, 2022, Microsoft only supports "Modern Auth", you can still use Basic Auth for SMTP authentication in your Auth0 configuration. If you are interested in Auth0 supporting "Modern Auth" for Office 365, please submit a feature request.
Prerequisites
To ensure that emails can be sent from Auth0 to your SMTP, open ports and allow inbound connections from specific IP addresses. To update the list of IPs, navigate to Auth0 Dashboard > Branding > Email Provider. To learn more, see Add IP Addresses to AllowList.
The provider must support LOGIN authentication and TLS 1.0 or higher.
You must have a certificate signed by a public certificate authority (CA).
Configure custom SMTP server
Navigate to Auth0 Dashboard > Branding > Email Provider.
Activate the Use my own email provider toggle.
Click the SMTP logo.
Provide a From email address, then enter your SMTP server Host, Port, Username, and Password. Common ports include 25 and 587. Please avoid using port 25 if you can because many providers have limitations on this port.
Click Save.
Test email
You can now send a test email using the Send Test Email button. If you have configured everything correctly, you will receive a confirmation email. If you do not receive an email after a few minutes, please check your Auth0 logs for any failures.
SMTP makes it easy to set up test services that allow you to test that your setup is working without spamming your users. To learn more, see Set Up Test SMTP Servers.