Please check when the doorbell is added to app, at notifications in the app. It needs to say, enable. Enter the setting and check if it is enabled and that it states receive and push event. Also check in the same screen if certain notifications are not blocked. I had this earlier and then nothing happened. The blocked event will pop up in the screen with receive and push.
I have the doorbell connected to nvr as well. So doorbell notifies with single photo and nvr with the corresponding video.
Also check on intelligent notifications and that you have set the area of which you would like to check.
When someone leaves the door or enters the door the notifications will pop up. If someone rang the doorbell, the same screen pops up, and when answer the call you will see live view within the app.