Mobile Device Management (MDM) software often controls access to corporate resources based on location, network, or VPN status. If the MDM is not configured to allow access from outside the office or via home networks, the apps may be blocked. This is the most probable cause if apps work only on-premises. * Option A: GPS is used for location services, not access control. * Option C: WPA is a Wi-Fi security protocol, not related to access restrictions. * Option D: NFC enables close-range communication - irrelevant to app access. CompTIA A+ Core 1 Exam Objective Reference: * Objective 1.6: Given a scenario, configure basic mobile device network connectivity and application support.