Custom SMTP Configured Successfully, but Allowlisted Users Don’t Receive OTP Emails

Problem Description

After publishing a documentation site and enabling Email Allowlist, users are required to receive a one-time password (OTP) via email to access the documentation.

The following setup has been completed:

Custom SMTP server is enabled

SMTP host, port, username, and password are configured

SMTP configuration test passes (for example, via cURL)

However, in actual usage, allowlisted users never receive the OTP email.

Possible Cause

This is a common issue caused by a mismatch between the SMTP port and the encryption settings.

Taking AWS SES as an example:

Port 587 does not use SSL encryption by default

If you configure:

Port 587

And enable SSL / encryption in the custom SMTP settings

The result may be:

SMTP tests appear to succeed

But transactional emails (such as OTP codes) fail to be delivered

Solution

Please review and adjust your custom SMTP configuration:

If you are using port 587

Disable the SSL / encryption option

Save the configuration

Try accessing the documentation site again to trigger the OTP email

If your SMTP provider requires SSL encryption, make sure the port you use matches the encryption method (for example, port 465 is typically used for SSL).

Applies To

Published documentation sites

Email Allowlist enabled

OTP verification via email

Custom SMTP servers (such as AWS SES)

Custom SMTP Configured Successfully, but Allowlisted Users Don’t Receive OTP Emails

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