Ring doorbell not resetting

Hello, I have a Ring Video doorbell 2. I changed my WiFi password and managed to update the details for all my other ring devices, with the exception of the ring video doorbell. I have gone through the set-up process many times, but nothing seems to work. Whatever I try, the video doorbell is not going into set up mode; after releasing the black button the light does not start to spin. I also tried holding for 20 seconds (or even longer), the light is not flashing; I don't think it is resetting. The doorbell is 100% charged. Any help would be appreciated since this is not working at all.