Why won’t my Root Pro coding robot stick to my whiteboard?

Information on vertical surface compatibility.

Please note that the Root Pro coding robot is the only model designed to attach to and navigate magnetic whiteboard surfaces. On some whiteboards with weak magnetic backing, the Root Pro coding robot might slip. Other whiteboards may not have any magnetic backing at all. Please note that you can still use a non-magnetic whiteboard with either model of the Root coding robot model as long as the robot is placed on a flat surface, such as a table or the floor.