Roblox logs me out every time I close the mobile app

So every time I close the Roblox app on my phone, whenever I open it again, I have to log in each time. Also, if I turn WiFi on or off I still have to log in again. Is anyone else having this problem or is it just me? If it’s just me, how do I fix it?

edit also, every time I open the app and go into a game, the mic is automatically on and I can’t remove microphone access from Roblox which is a problem because it turns the game sound into shit