Why does my overview button not function?

I’ve reported this problem again but I got no answer. So let me get this straight. I have a lenovo tab, I’ve tried anything possible (safe mode reboot, different launcher etc.) but my overview button (square) does not show my recent open apps. As soon as i press it the message ‘Your recent apps appear here’ pops up. The apps are still running in the background and this can be understood because when I reopen them them they are left off at the same point they were before closing them. The strange thing is that by using a different account, for example the guest one, the button is working perfectly. Also, the problem is not caused by an app because I have already done the safe mode reboot. Soooo please, I’m desperate for help. Factory reset or deleting cache files is not effective. Is there any setting for that? I just need helppp m8’s.