Data source information is not found in Power BI service

Hello, I would like to automate the DataSet generation (using C#). In this context, I have encountered a problem when I create the DataSet in Power BI Service.

My requirements:
- PPU (Premium Per User) Trial License
- On Premise SQL Server
- Microsoft.AnalysisServices Package

To generate my DataSet I complete the following steps:

1. Connect to Power BI Service
2. Create DataSet
3. Connect DataSet with data source (SQL server)
4. Bring tables from the data source into the DataSet

The code for this:

string workspaceConnection = "powerbi://myWorkspaceURL";
string ConnectionString = $"DataSource={workspaceConnection};";
using (Server server = new Server()) 
{
   server.Connect(ConnectionString);

   // Database Creation
   string newDatabaseName = server.Databases.GetNewName("CSharpDataSet_Test");
   var dbWithDataSource = new Microsoft.AnalysisServices.Tabular.Database() 
   { 
      Name = newDatabaseName, 
      ID = newDatabaseName, 
      CompatibilityLevel = 1500, 
      StorageEngineUsed = StorageEngineUsed.TabularMetadata
   };
	
   // Adding Data Source
   string dataSource = "LocalSQLServer";
   dbWithDataSource.Model.DataSources.Add(new ProviderDataSource() 
   { 
      Name = dataSource, 
      Description = "Description Example", 
      ConnectionString = "Provider=SQLNCLI11;Data Source=LocalSQLServer;Initial Catalog=MyDatabase;Integrated Security=SSPI;Persist Security Info=false;",
      ImpersonationMode = Microsoft.AnalysisServices.Tabular.ImpersonationMode.ImpersonateAccount, 
      Account = @"MyAccount", 
      Password = "password", 
  });
	
  // Adding Table/Columns
  dbWithDataSource.Model.Tables.Add(new Table() 
  { 
      Name = dbWithDataSource.Model.Tables.GetNewName("Individual Customers"),
      Description = "Table Example Description.", 
      Partitions = {
         new Microsoft.AnalysisServices.Tabular.Partition() { 
            Name = "All Customers",
            Mode = ModeType.Import,
            Source = new QueryPartitionSource() { 
	       DataSource = dbWithDataSource.Model.DataSources[dataSource],
               Query = "SELECT city, street FROM customers"
            } 
         } 
       }, 
       Columns = 
       { 
          new DataColumn() { 
	     Name = "City", 
             DataType = Microsoft.AnalysisServices.Tabular.DataType.String, 
             SourceColumn = "city", 
          }, 
          new DataColumn() { 
	     Name = "Street", 
             DataType = Microsoft.AnalysisServices.Tabular.DataType.String, 
             SourceColumn = "street", 
          }
       }             
  });
	
  server.Databases.Add(dbWithDataSource);
  dbWithDataSource.Model.RequestRefresh(Microsoft.AnalysisServices.Tabular.RefreshType.Full);
  dbWithDataSource.Update(UpdateOptions.ExpandFull);
}

With this code, I am getting the following error in the last line of my code (dbWithSource.Update(UpdateOptions.ExpandFull)):

{"error":{"code": "Premium_ASWL_Error", "pbi. error":{"code": "Premium_ASWL_Error", "parameters":{}, "details":[{"code": "Premium_ASWL_Error_Details_Label", "detail":{"type":1, "value": "An unexpected internal error happened while obtaining the credentials for the data source '<ccon>13</ccon>': data source information is not found in Power BI service."}}]}}

Upon further investigation, I notice that the error only occurs when the Column part is present during table creation. If I comment the column part, then the error does not occur.

My Questions:

- Is it possible that I have the problem with my code that I connect to my Power BI Workspace at the beginning, but then I specify a local(on premise) database as data source and because of that it says "Data source information is not found in Power BI service"?

- Could I also connect to a Local Power BI Report Server instead of a Power BI Workspace?

Because of my described problem, I am also trying now to generate the DataSet within a Power BI file in an open Power BI Desktop instance. In doing so, I am running into an issue with the enhanced metadata format (See How do I use the enhanced metadata format in C#? ).

In addition, I have revised this thread and merged information from my reply post for Anonymous into my initial post for improved understanding and clarity.