Hey 4besko,
Welcome to Apple Support Communities. The information in this article may help explain why your iPhone is showing offline: If Find My is offline or not working.
"I see my device in Find My, but it's offline
Learn why you might see "Offline," "No location available," or "Location Services Off," and what to do.
Why is it offline?
- Your device is powered off or its battery has run out.
- It's not connected to a known Wi-Fi or data network.
- If you turned on Send Last Location, more than 24 hours has passed since it connected to a Wi-Fi or data network.
- You might be in a region where we don't offer this feature due to technical limitations or local law.
What can I do?
You can still play a sound, send a message, issue a lock request, or start an erase of your iOS device with Find My. Your device receives the command after you turn on your device and connect to the Internet."
Take care.