Alarm Siren backlight

Hi everyone. I've installed a ring alarm system with the external siren. I've hardwired it using a 12v DC 1A power supply and it's showing in the app as hardwired+ D batteries. Ive switched the dusk till dawn backlight on in the settings. But it is not illuminated. A neighbour said it was lit at 7am in the morning but I've not seen it lit and I've checked from sunset (5pm) till 9pm and it's still not on. Any ideas what's going on? Could it be coming on at the wrong times some how? Thanks