GoKawiilApple explains fixes for iPhone Always-On Display shutting off
Apple's Always-On Display keeps a dimmed Lock Screen visible on supported Pro-model iPhones, but some users find it fully turns off instead of staying dimmed. The feature is limited to iPhone 14 Pro and later Pro models plus the iPhone Air, and can be toggled in Settings under Display & Brightness. Several common settings issues can cause it to malfunction, each with a simple fix.