An App ID with identifier is not available in developer.apple.com

Question

I create flutter application.I am trying to create App id in developer.apple.com for firebase messaging, After create and add Bundle id I got this error:

An App ID with identifier 'com.........Mobile1' is not available.

and in xcode:

Answer 1

as the error suggests bundle identifier string you are trying to use is not available because somebody else has uploaded and published and app to the AppStore with that identifier, you need to change Bundle Identifier to something else that is unique to your application

for example :

com.example.myuniqueidentifier
com.mydomain.myuniqueidentifier