The existing feature requires all domains to be marked as trusted to proceed with data migration else the migration will be blocked, as detailed in the following documentation: Review Users to Trust Email Domains.

The requirement is to have the capability to allow the migration by marking specific domains as untrusted. This will allow customers to exclude users associated with these untrusted domains from being migrated to the cloud.

This selective trust feature would enhance flexibility by enabling organizations to better manage their data migration process and adhere to their specific security and compliance protocols.