Rear door not opening
 

2005 X5 3.0i

I was dropping off my daughter at school and she could not open the rear door. I tried opening from the outside too but didn't work. Can someone tell me how to open the panel to see what's wrong with the door latch? Thank you.

Classic problem of bad lock actuator.
This has been discussed multiple times in E39 forum.

Your best bet: keep trying with the remote for many days. If you are lucky, one of these days, the actuator will work for the last time. If that happens, do NOT lock the door again.
Instead, use that opportunity to remove the trim panel from the door first!

Remote locking/unlocking works fine. Handle from both outside and inside doesn't seem to engage or work. How do I open the trim panel. I see instructions on front doors with airbags only.