Originally Posted by andrewwynn

Double lock motor failure.

Try the double lock inside override. (sit inside the car, use key fob to lock the car, press twice to deactivate the motion alarm, then hold the central lock button and at the same time pull the door handle inside.

If child lock engaged I'm not sure if the double lock will stay off and you can subsequently unlock from outside.

The next most likely candidate is that one of the release cables is not returning fully to reset the latch. You will have to wriggle off the inside panel to get to the door actuator, usually disconnect the cable/s and manually pull the latch lever.

If the double lock motor is dead you can manually flip the double lock but it's tricky to get to it as it's covered by the weather protection.