Hi Sean,
First, only classes in ArcGIS.Core can be used in a console application. These are Geodatabase and Geometry classes. None of the classes in any of the ArcGIS.Desktop.xxxx assemblies can be run using CoreHost so even if you get past the license check in CoreHost at runtime your console app will crash in spectacular fashion.
Second, the message you are getting is coming from the Pro license check (I assume you are on Backstage in Pro?). From the error message content it seems you have already taken Pro offline on another machine. You must check in that license first (on that machine or device). You can find more information here: http://pro.arcgis.com/en/pro-app/get-started/view-software-licenses.htm Topic "Authorize ArcGIS Pro to work offline"
If this is not the case and you do not have your license offline on another machine or device then you will need to call ESRI tech support to resolve the issue.