Flutterflow push notifications app icon in the top of the screen is a white box instead of the app logo

Hello,

I have enabled push notifications in my app and facing an issue.

In the top of my smartphone screen, when a new push notification arrives, instead of showing the app's logo, it shows a white box (empty?).

How can I replace that box with the app's logo?

P.S. this happens in both Android and iOS