Hi,
Thank you for your feedback. Via my search, you can deploy it on Windows server 2019 by some configurations. Here are some hints for you.
Validate Active Directory prerequisites
https://learn.microsoft.com/en-us/windows/security/identity-protection/hello-for-business/hello-key-trust-validate-ad-prereq
Planning an adequate number of Windows Server 2016 or later Domain Controllers for Windows Hello for Business deployments
https://learn.microsoft.com/en-us/windows/security/identity-protection/hello-for-business/hello-adequate-domain-controllers
If you are planning to use Windows Server 2019 domain controllers refer to KB4487044 to fix this issue.https://support.microsoft.com/en-us/help/4487044/windows-10-update-kb4487044
Best Regards,
Grace
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