all devices and configuration in android app are disappeared

since a few weeks, all my devices (doorbell pro 3 elite & chime) are disappeared from the ring app. the Doorbell is connected mit PoE-cable and internet connection is stable and fast. I cannot not reconfigure it cause is still in use. what else can I do? For your information, I have already verified these potential problems: - internet connection: stable and fast, doorbell is connected to PoE-cable - Smartphone Samsung Galaxy S9 (WLAN & Internet connection are stable and fast) - Ring App uninstalled and reinstalled - I've tried to add the devices again, but I can't because it is still in use Many thanks for any solutions