Based on your error message, I can determine that the application group identifier you selected is unfortunately used by someone else but your team. And based on this you need:
Create a new application group:
Create a new application group with a different identifier, i.e. group.com.company.newappgroupname. The smoothest way is open your project in XCode, then open the info on targetand then open the " Capabilities" tab . Here you will find the groups of App Groupsyour team and the ability to add new ones (by clicking on the + sign). Here you also choose that your application will "join" to a specific application group by checking the box.
Optional - if you want to remove the application group:
XCode, Apple ", ". → . . , . . , , . !