Hello there ^^
There could be many things causing this problem, such as low internet connection, glitching, ect. When you go into a map (for me) it say's "Not Responding" and then if you click again your screen shall turn white. That's normal, let it do that for a few seconds and then you'll pop right into the game. But if it "Looses Connection" then go onto the forums and reset your character's home and try again. If it just keep's happening I would suggest to maybe redownload your game.
I hoped this helped~~~Sammy