Your refrigerator needs to stand level on its feet to function properly. Try rocking the appliance from side to side or back and forth. If it is wobbling too much, your flooring or the appliance's feet may be uneven.
Use a spirit level to check the appliance's balance. If it's off, adjust the feet by reaching under your refrigerator and finding the two front feet. Turn the feet clockwise or anti-clockwise, until they are firmly in contact with the floor.