Microsoft Defender Antivirus(AV), which is required to make use of Huntress Managed Antivirus, does not come pre-installed on Windows Server 2012 R2. To take advantage of this new feature you first need to install Microsoft Defender for Endpoint (MDE) on your server following Microsoft’s instructions. Once installed, that will also install Microsoft Defender AV on the server which can then be managed by Huntress Managed AV.
By default, Huntress will classify all Windows Server 2012 R2 endpoints as Incompatible. If we detect that MDE is installed on this OS, we will begin monitoring and displaying AV health; we will also allow the endpoint to be managed by Huntress (allow Enforce mode).
You can check all of the supported OS for Managed AV.
NOTE: Managing policies through both MDE and Huntress Managed AV could cause unintended conflicts. If you wish to manage or support policies through MDE, make sure Huntress is set to Audit to avoid conflicts.