I have the same problem in that I cannot access the Ring doorbell whilst in Win 10 Alexa app. Alexa just says that it is not accessible on this device.
I suggest somebody gets this sorted asap. I have 4, soon to be 6, Stick Up Cams and a Ring Doorbell, I want them accessible from all my devices not just a phone. The Ring adverts suggest it is simple to access your home cameras, but it is not at all !
I have had to give all the cameras and doorbell static IP addresses as the so called easy setup was abysmal and did not work correctly. It took so long to access the doorbell whoever rang the bell had long gone.