I would say two things happened:
You got air in the circ pump and overheated the heater, tripping the reset button.
You tried to reset the heater, but it still had enough heat in it to keep it from resetting.
You shut down overnight, allowing the heater to cool, and the air bubble in the circ pump to move, clear or go away, so:
when you turned the power back on, everything worked as it should.
Remember to turn on the 30 amp breaker first (for pumps) and then the 20 amp breaker (for heat) after running the jets for 10 minutes.