Can somebody assist me

Hey, im new to recreation dev particularly for android app improvement, im practising and i’ve this prototype apk for android, it’s an AR app that i made utilizing Unity and vuforia, the issue is that after Putting in the app and working for the primary time the AR perform works, but when i shut the app after which open it once more the AR perform doesnt work anymore

that is my first time creating anaandroid app, it’s for my capstone and im dire of need assistance

ps: im only a week since i began utilizing Unity additionally the Unity model is 2023.2.20f1 and Im utilizing Vuforia engine for the AR perform the ver of vuforia im utilizing is 20-24-4