Was the green ready-to-drive light lit?
Sometimes you can fool yourself into thinking the car is working if you can just "roll" out of a spot due a slight incline (with the ready-to-drive light not actually on).
The ready-to-drive light might not come on if you shift out of park too quickly after turning the car on. This is a relatively common problem for FFE owners, especially new.
After you turn on the car, always verify that the green ready-to-drive light is lit before doing anything else. Over time, you learn to make it a habit to give the car a second or two after pressing the power button. Then, the "not ready-to-drive" issue doesn't really happen anymore.