Maybe it has been a while since you used Binance Exchange, and they might have logged you out automatically. Try and re-login with your details and try again because there is no general issue related to this, although they do have network issues sometimes.
 
I was logged out of my Binance app too; I just logged back in, updated my Binance app, and everything was working perfectly as usual.
 
Maybe you will consider updating your application, or maybe they have restricted you from using their service.