First of all please don’t change anything with is not mention in document or video. If you know the code flow and understand then make the changes.

This error is coming when you change the package from AndroidManifest.xml file or change folder name. No need to change this it does not affect your app.

Only you need to change applicationId on build.gradle file. And after the change must update your firebase file. applicationId is the unique application name form your app.

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