VPN may not work for various reasons. Some of them include: 1. Issues with the internet connection. 2. Multiple VPN applications installed on the device, causing conflicts. 3. Planet VPN has a Killswitch feature that blocks traffic in case of a VPN connection failure. 4. The VPN application may be outdated. It is recommended to install the latest version. 5. It might be necessary to connect to another server. If problems persist, contact customer support.