Logged out for no reason

From time to time i get logged out from my computer after leaving the computer for some time to go cook dinner, or something else that might make me leave the computer for a while. I usually press Windows + L to make sure nobody tampers with the computer, but when im back i get the log in screen, but its just thinking. I refresh, and i see my two other accounts, but not my main one. So i have to manually click on add a new account, scan the QR code because I can't remember my password, since i got a new phone and the 2 factor verification doesnt save across platforms, is what i have to do possibly every 1-2 weeks. I do not know what is causing this, or if this is happening to others.