steam guard not showing code

So i downloaded the steam guard app to my other phone and logged in on it but it does not show any of the codes for authentication, in place of the code there is just this steam logo. I'm also currently logged in on steam guard app on my other phone and the code is showing on that phone, i don't want to log out on that phone because it may experience the similar problem. Can't I have access to 2 phones with the steam guard app with my account logged in?