Hi Morgan,
Sorry for the inconvenience caused. Due to some technical problems, Nuget feed ‘ http://nuget.syncfusion.com/dashboard/aspnetcore’ is down at the moment. As a workaround, you can refer the package manually from the below mentioned location. Please add this location as a local Nuget feed.
%localappdata%\Syncfusion\Dashboard\Samples\Common\Precompiled Assemblies
Regards,
Mukil K.