I have had a "DOORS" caption pop up before on the 737 - the QRH suggests you remain below 10K/descend and depressurise if pressurisation is not normal, but if it's normal you can continue normal flight.
In our case it was a duff sensor that was dealt with at our destination.
Unlikely to be open - at least 3 opportunities for the crew alone to catch it I can think of prior to departure.