In order to fix the issue, launch the Inter-Tel 5000 DB Programming DB software, expand the System list and then the Devices and Feature Codes one. You will find all the extensions in the Endpoints menu. Select a extension that works OK and check the parameters from the Forwarding Paths section. After that, use these parameters to configure the extension that rings back to the operator. If you have issues, use the contact information from the official web page to get in touch with the developers.