What does it mean if it says "you have been kicked from the game session"

That means that the starter of the session kicked you out. Could be because he wants his friends to join or just don't want you in that lobby.

@CrazyDavewins Hi, what system are you on? Do you get the kicked message in both competitive MP and garden ops?

If you're on PC do you get an error mesage when it shuts down?

Edit: I saw your other post here: https://answers.ea.com/t5/Technical-Issues/PVZGW2-My-game-crashes-and-doesn-t-work/m-p/6858088/highlight/false#M5586

Thanks.