Application.Download MemoryStream

Hi,

when I try to perform a download on the web server (IIS10) using the method below, I only get an empty file. Locally in VS with IIS-Express it works fine.
What permissions are necessary on the Server?

Method:
public static void DownloadAndSave(DataView dtData, string FileName)
{
string data = ExportDataToCSV(dtData.ToTable());
MemoryStream myStream = new MemoryStream(System.Text.Encoding.Unicode.GetBytes(data));
Application.Download(myStream, FileName);
AlertBox.Show($”Die CSV-Datei ‘{FileName}’ wurde erfolgreich heruntergeladen!”, MessageBoxIcon.Information, null, System.Drawing.ContentAlignment.MiddleCenter, 6000);
}

THX,

Stephan