Why might push notifications not work?

Question

ASP.NET

Please, tell me, I've already broken my head, I can't figure out push notifications in the browser (Chrome).
It seems that I did everything, but they still do not come
1) I made the client part of the subscription based on the materials
https://developers.google.com/web/updates/2015/03/...
https://mobiforge.com/design-development /web-push-...
https://developers.google.com/web/fundamentals/get...
The service worker is created normally, the new endpoint is displayed in the console
2) I send data to Google via the
www.codeproject.com/Tips API /434338/Android-GCM-Push-N...
I get a successful response (some ID like id=0:1469533196433859%13b6677a66d6cf16 )
Google Cloud Messaging API enabled
I don’t understand, notifications should pop up immediately after I sent the request, or will Google send them after some time?