Sebastian is the hr department's trainer. He is developing various materials to teach the fundamentals of using a virtual private network (vpn) to a variety of audiences, from the president and vice presidents of the corporation to newly hired mid-level managers and entry-level employees. After implementing his training program some weeks ago, he began getting calls from the it help desk stating that users are contacting them with troubleshooting issues for their vpn sessions. The help desk technicians do not know how to respond. What is the most likely problem?