The "No location found" message in Find My on a new iPhone can be due to a few reasons: the person may have turned off location sharing, their device might be offline, or there could be a problem with their settings or your own. To troubleshoot, ensure location services and Find My are enabled, that the person is connected to the internet, and that they haven't turned off location sharing specifically for you.
If the other person's device is turned off, in Airplane mode, or has no internet connection, their location won't be available.
There might be a temporary problem with Apple's location tracking services or with the Find My app itself.
Reset Location & Privacy: If all else fails, you can try resetting Location & Privacy settings on the affected device (Settings > General > Transfer or Reset iPhone > Reset > Reset Location & Privacy).