All Email Security Gateway models 300 and above, all firmware versions.
If you are unable to create new users on the Users > User Add/Update page, it could be because the Email Security Gateway is unable to send the initial welcome message to that user. This happens when an incorrect Outbound SMTP Host/Smart Host has been entered on the Basic > Administration page, or when that SMTP host is unavailable. Check that option on the Basic > Administration page, and if anything has been entered into the Outbound SMTP Host/Smart Host field, remove it - this will probably resolve the issue, as the Email Security Gateway can deliver quarantine welcome messages and notifications to users without an Outbound SMTP Host/Smart Host configuration.
Link to This Page: