An attribute in the provided entity has invalid value An App ID with Identifier 'com.mycompanyname.app.mobile' is not available. Please enter a different string.
I am encountering this error, but I cannot solve the problem, I request your urgent support.
Someone else might have that bundle ID, or Provisioning Profile might be expired:
I am getting the same error message and since this is my first app, and I am using my website name in reverse DNS format, I know the bundle does not already exist.
The following worked for me. Looks like we have to include the team id (generated by Apple) in front of the bundle identifier when registering an identifier in the developer account. Current syntax is AG23SE13.com.domainname.appname. For more information, click on the following link, and click on APP ID. A popup will appear with the details: