Door handle will not open door?

Hello,

This is likely due to a broken component inside the door handle.
The door handle is attached to lever that releases the door latch. Over time due to wear that lever can get disconnected or broken off of the handle. This will make the handle inoperative.
So, the broken piece can be the mount on the door handle or the lever itself.
You will have to remove the handle to see which is the broken piece.

I have attached diagrams showing the replacement procedure below.

Please let me know if you have any questions.
Thank you.