View federated-authentication user name conflicts in Apple Business Manager
After a domain is successfully added, Apple Business Manager reviews all existing Apple IDs by searching for any using that specific domain name. If an Apple ID is found to be using the domain name, Apple Business Manager lets you send a mail message—and a notification to any device connected to their iCloud account—to that person, letting them know they must update their Apple ID user name so that you can use it for your organization. They don’t have to change their password and all their purchases and data remain in their account.
For example, say your organization registered the domain @acme.com several years ago and set up email addresses for all their employees. Jane Appleseed decided to use the email address she was assigned “firstname.lastname@example.org” as her personal Apple ID.
Even if Jane no longer works for the organization that registered acme.com, she still has the Apple ID with that domain name. Because you are setting up federated authentication for the domain name @acme.com, Jane must change her Apple ID user name so you can create the Managed Apple ID email@example.com if you want.
View federated-authentication user-name conflicts
In Apple Business Manager , sign in with an account that has the role of Administrator, Site Manager, or People Manager, then click Activity.
Click Checking for Conflicts.
If any user name conflicts are found, you’ll see a dialog with the total number of user name conflicts.
Click Continue, click Send Notifications, then click OK.
A mail message—and a notification to any device connected to their iCloud account— are sent, letting each user with a user name conflict know they must change their personal Apple ID.
You can view the process of sending mail messages to users with a user name conflict in the Activity section of Apple Business Manager.