If you need Find My iPhone (now Find My), you’re probably already in a stressful situation: your iPhone has been lost or stolen. That situation is made worse when Find My isn’t working.
Find My says "No location found" on iPhone? How do I fix this? [iOS16 supported]
To get Find My working again, follow these steps in order. These solutions apply when you have your device in hand and can change the settings.
Charge your device. While an iPhone running iOS 15.2 or later can still broadcast its location when it’s in Power Reserve mode (when it has battery left but not enough to turn on), a completely dead device won’t be able to broadcast its location.
Check your Apple ID. You can’t use Find My with a different Apple ID than the device you’re looking for. On your phone, go to Settings > [your name] and look at the email address under your name. This is the account you’ll need to sign in to iCloud to find your phone.