No push notification received on phone

I followed the push notification android setup . I ionic build for android and then email myself the .apk. I download the app on my phone. I run it, go to the push tab and click “Register”. An alert box with the device key pops up. All good in the hood.

When I go to the push page for my app ( and create a new notification:

I turn it on and it all looks good. My app has one download, from me emailing it to myself and downloading it. I still have not received any push notification on my phone though. Does it only work for apps deployed on google play? Why can’t I see the push notification on my phone after I download the .apk for my app?

I wrote up a blog post for the steps I took, following the docs closely: