Is your Nest Aware subscription set up in the same "home" as your doorbell? If you go into the Google Home app (or the Google Nest app for the Nest Hello doorbell) and select Settings | Nest Aware, does it show your subscription?
Also, you should be able to access your subscription here:
Sorry for the late response here, but I wanted to check in to see if you were still having this issue and to see if you have done any troubleshooting so far. If you still need help, let me know and I'll be happy to work on this with you. Thanks to MplsCustomer for the help and input here.