Please follow the below steps to trust the mobile app

• Starting from iOS 9, the developer has to be trusted by the device, otherwise a popup will appear and prevent using the app.
• On iOS 9.0/9.1, Go to Settings > General > Profiles > President TN Police Unit Canteen > Trust "President TN Police Unit Canteen" > Select the "Trust"
• On iOS 9.2+, Go to Settings > General > Device Management > President TN Police Unit Canteen > Trust "President TN Police Unit Canteen" > Select the "Trust"