Disconnects when joining Lan worlds

I wanted to play Minecraft with my brother but after I join on his world I randomly gets disconnected and I have to restart Minecraft to join again and it gets disconnected again.. and he joined to my world and he also gets disconnected. so we can't play for a long time cuz the one that joined the world just gets disconnected and also when breaking blocks it's kinda lagging... if you have the same issue then that's so sad... pls fix this ..... love: ToolDroid