Night vision not working Ring Doorbell 2

Recently despite good connetion and device health I get totally black screen videos at night when I used to get night vision videos at night. I keep reading that there is a way to turn nightvision on and off in the app, but there is no such setting in my Ring App. I have already followed the suggestions to check my device health and wifi signal near the device (both well over the minimum). It is working perfectly in daylight, problem is just at night. Any ideas? Thanks!