User with custom domain does not appear in "Microsoft Defender 365/Assets/Identities

I Have all licences
Workstation onboarded in MEM

Sensor installed on DC's
Everythings looks fine.

Every user with the default mailto:email address removed for privacy reasons is onboarded, but user that I've synch with On-prem DC's does not.

Did I missed something ?

I'm confuse.

Thanks for the help,

jasmin