Display says "OOO" (Out Of Order)
There has to be 1 block of air and elevator rails below the lowest floor!
There has to be 1 block of air and elvator rails above the last floor!
Make sure you have proper solid floor around the elevator shaft!
To fix an elevator that displays "OOO"
Right click on the elevator with the technical wrench -> Update. Then call the elevator on some floor.
Break the elevator with technical wrench and replace it.
Stuck in an elevator
Go into the spectator mode (F3+N) and move away. Then switch back.
This elevator build does not work properly!
Make sure you have some blocks where the green blocks are!
Without those the elevator will break.
At the moment villagers can use the elevators only when somebody opens the doors and pushes the villager in.
It is possible to push any entity (like a sheep) into the elevator, but other entities will not select the floor themselves.
Pedestrians can use elevators themselves.