The email queue can be restricted to accept emails from registered users only. When enabled, non-registered users will not be able to send emails to that queue, and they will be prompted to register at the help center first. This setting helps to fight spam emails.
This article provides instructions on how to restrict the email queue to accept emails from registered users only.
Sign in to Kayako and go to the admin area.
Go to Email Parser and click on Email Queues.
Click on the email queue address you want to configure, example:
Click the Ticket Options tab.
In the 'Registration required' section, select Yes.
Click Update to save the changes.