NX rear hatch will not open

[Grumpycatforever]

I have an nx200 and the hatchback will open (automatically when pressing the button on dash or key fob) 30% of the time.  The rest of the time it just beeps (long beep) and then fails to open so I have to do it manually.  The Lexus dealership wanted to replace the hatch back motor but since it works some of the time is that really the problem?  Any advise is appreciated. 

[RX400h]

This can happen of either there is an obstruction in between the door and the interior or the gaskets are sticky for some reason. I've lubricated our RX door seals with ArmorAll and this does help. A 7 year-old vehicle should not need a hatch motor unless you are opening and closing it automatically 6 times a day.