P38 Lower Tailgate stuck closed

I have a '97 Rover and the lower tailgate will not open even thought I can hear the actuator click when I press it. It once did this before when the passenger front door actuator was inoperative and had to be replaced. Is there a way to trouble shoot this or diagnose this? The top tailgate works fine.

Thanks :confused:

Red Rover

my is getting pretty sticky and I have to push on the tailgate while pushing the button and it opens without problem. let me know if you find the cause.