Can’t link admob with firebase iOS/Android project

I have two accounts: “A” and “B”:
A is main account that hosts iOS/Android unity mobile game on Firebase.
B is using for admob integrated to iOS/Android mobile game.

I’m getting error when trying to link admob analytics to the Firebase project.

I shared firebase project with B by granting permissions as “owner”. So account B currently has all access to Firebase mobile app game.

When I’m trying to link admob with Firebase in “App settings” next error appears:

Can’t link to this Firebase project. Make sure you have sufficient
permissions and try again.

enter image description here

How to solve the problem above?

Source: Ios