Game Made in Canvas Showing Bugs Multiplayer

Hello there, i have made a 2DGame in Unity canvas, this was my first 2d Game, and the issues i am facing in this game is, all images setup according to device's resolution, and this is a multiplayer game, if my cannon fire,it hit the opponent in my device but in opponent's device it don't hit at the Cannon, it might hit on any hurdle or fall somewhere else. just because of screen hight and width, i am stuck, cant find any solution,