Exception when referencing SSAS tabular model in C #

I am trying to automate section updates in Azure Analysis Services via C #. I have installed and referenced the latest 'Microsoft.AnalysisServices ...' collected here:

https://docs.microsoft.com/en-us/azure/analysis-services/analysis-services-data-providers .

Then I have the following code:

using System; using Microsoft.AnalysisServices.Tabular;

    public void Run()
    {
        Server asSrv = new Server();

        try
        {

            asSrv.Connect(ASConnectionString);
            Database db = asSrv.Databases.FindByName("HospoIQTabular");
            Model m = db.Model;

            // only refresh 2017 partitions

            m.Tables["Sales"].Partitions["Sales - Post 2017"].RequestRefresh(RefreshType.Full);
            m.Tables["Payments"].Partitions["Payments - Post 2017"].RequestRefresh(RefreshType.Full);

            db.Model.SaveChanges();     // commit which will execute the refresh

        }
        catch (Exception e)
        {
            OnEventLog(e.Message);
        }
        finally
        {
            asSrv.Disconnect();
            asSrv = null;
        }

    }

      

        
        
        
      

    

The server connection and the database itself works great. However, trying to reference "db.Model" throws the following exception:

The value "2" is unexpected for "DataSourceType".

I have looked but cannot find anything in this. Any thoughts?