Push not working properly

When I receive a push notification on Android and my app is open I receive the push on push.on(“receivedMessage”, function(payload)…

But when my app is on background or closed I dont receive the push in my notification bar! This work fine in previous versions! Now in 1.8.2 is broken!

How can I fix this?

Tested on Android 8.0

Maybe is this: https://stackoverflow.com/questions/43093260/notification-not-showing-in-oreo

How can implement it?