Hi dirk293,
Thank you for posting in the Apple Support Communities. From my understanding, a third-party Bluetooth device isn’t connecting properly to your daughter’s iPhone. I’d like to share some information with you that might help.
First, follow these steps: If you can't connect a Bluetooth accessory to your iPhone, iPad, or iPod touch
Next, you might want to try unpairing, then pairing them again to her iPhone. I also recommend trying to pair it with another iOS device to further isolate the issue: Pair a third-party Bluetooth accessory with your iPhone, iPad, or iPod touch
Additionally check for sources of interference: Resolve Wi-Fi and Bluetooth issues caused by wireless interference
I hope this helps get you started. Kind regards.