You are talking the hatch right?

If your battery is about 4 years+ old it might be low voltage? You could attach battery charger and see if it then works. Now I doubt it will but the battery needs to be eliminated as a possibility.

Could be a fuse sense totally dead, check that.

Is there a emergency mechanical method to open it? I sure hope so because otherwise I wonder how you can get to the possible problem area.

Seems to me you likely will need to get to the hatch electrics and check voltage at the actuator that opens the hatch. If you have voltage.then the actuator is bad if you have no voltage well why not?