I once received a call for the elevator broke down at dusk. Of course they didn't want to pay for over time. The next morning we arrive and the elevator was running. At the end of the next day, (you guessed it) the elevator went down at dusk.
What we found was when the new outside lights went on at night, the voltage dropped enough to shut the elevator down.

Sometimes you have to look outside (no pun intended) of the elevator system.