FirebaseApp is not initialized

[gsstudio]

Hi, I'm trying to use this plugin, but it gives me all kinds of errors with Firebase initialization, even the test solution you have here.
I have tried all the solutions that are here and other pages and I cannot solve the problem. I get the following error.

Default FirebaseApp is not initialized in this process . Make sure to call FirebaseApp.initializeApp(Context) first.'

Victor

[MichaelFatziVAPC]

same problem here.
google-services.json is in the root folder with build action "GoogleServicesJson"

[LinMoskovitch]

Same problem as Victor here.