When you want to add a CTI user to AE Services, you must use the User Management Menu in the AE Services Management Console. That is, the AE Services Management Console Security menu (Security > Security Database) does not allow you to add a CTI User. See Adding a user to User Management.

Service Management (which controls User Management) periodically runs a synchronization process to update the Security Database. When the newly added user appears in the Security Database, you can assign user permissions for the newly added user. See Administering CTI User settings.