FPS counter not working for games.

Basically title. I can’t seem to get Razer Cortex to show my FPS in games like Roblox. I have already found a solution which is literally go to another user that is the admin (Thanks, Mediamarkt for bloating it and already setting it up even tho i wanted to) and get Roblox from there, but that’s really about it… Do I need to run the game on my normal user through fullscreen? PLS help!!