https://www.bleepingcomputer.com/news/microsoft/microsoft-defender-for-endpoint-fails-to-start-on-windows-server/

Microsoft has confirmed a new issue impacting Windows Server devices preventing the Microsoft Defender for Endpoint security solution from launching on some systems.

The enterprise endpoint security platform (previously known as Microsoft Defender Advanced Threat Protection or Defender ATP) might fail to start or run on devices with a Windows Server Core installation.