Push Notification custom icon

[jtejedera]

I'm trying to change the icon in a Vue + Capacitor Push Notification Plugin. It seems that by default it is taken the default app icon, which is correct, and when a push notification is received in the background, Android shows the app icon, but when I slide down the notifications, it showsa grey square.

I tried to change the icon following the guide by adding the next line in AndroidManifest.xml:

<meta-data android:name="com.google.firebase.messaging.default_notification_icon" android:resource="@mipmap/push_icon" />
Then I created a new Image Asset in android studio with a new image called push_icon, which is then located inside /res/mipmap/push_icon, but it is still not working.

What I'm missing?

Thank you.