“Configuration error. No migrator configured.” when running MigrateUsers

Migrating a SP Server 2019 site to claims and running MigrateUsers($ true) fails and puts this in the logs for every user and group.

Configuration error. No migrator configured. 14f7e39e-845f-6002-7dbe-fa871f2660cd SPUser ’13’: Could not get migration data for entity so SKIPPING. Check migrator for further logs.

I’ve set up Active Directory Import and it’s importing users but I’m not sure if the configuration is correct.