Your Ring Pro requires a power source that supplies a minimum of 16 volts AC at ~20 volt-amps when connected directly to a transformer, plug-in adapter, or ~30 volt-amps when used with an internal doorbell. To check the voltage of your Ring Pro, open the Ring app, select your Ring Pro, and tap Device Health. For Ring Pro to function correctly, the voltage needs to be at least 3, 700mV. If the voltage is below that number, device functionality will be impaired.