An App ID with Identifier 'com.example.app.extention' is not available. Please enter a different string

Question

I have tried to add extensions to my iOS app, both a today extension and an Apple Watch app. My app has been completed however when submitting my archive I got the error bas

Answer 1

For a typical bundle ID such as com.mycompany.appname, the App ID name must be in this format:

XC com mycompany appname a name in any other format won't be seen by Xcode.