Unresponsive Doorbell with solid White Circle

HiAfter charging the doorbell has a permanent full white circled light, but won’t enter pairing mode etc. I can hold down (10 secs) the orange button to force a restart, but it instantly reverts straight back to the full solid round light. Pressing the orange button and releasing straight away does not start pairing mode. Tried disconnecting from my account within the app, but now cannot reconnect it and it appears to be locked. Unit must be holding charge as the solid light remains on despite being unplugged. If I press the button as if I’m a visitor the bell will chime (sometimes, but not always) but then always reverts back to the solid light.