Diagnosis
The automatic light settings are either misconfigured or the camera's ambient light sensor isn't triggering the 'night' mode correctly.
How to Fix It
In the Ring app, go to your device, then to Light Settings. Make sure 'Schedule' or 'At Night' is selected for when the lights turn on. If it's on 'Schedule', verify the times are correct. If it's 'At Night', the camera decides based on its sensor. Also, check the 'Light Brightness' slider—it might be set to zero.
If That Didn't Work
The sensor might be blocked or confused. Clean the camera lens and the small light sensor window (next to the lens) with a soft, dry cloth. Also, check if a nearby porch light or streetlight is tricking the sensor into thinking it's daytime.
Heads Up
The 'Motion Activated Lights' setting is separate from the general light schedule. If you have that turned off, the lights will only come on manually or via a schedule, not from motion, which catches a lot of people out.