I have implemented a custom button on the Content Editor which triggers a Custom command(which inherits from Sitecore.Shell.Framework.Commands.Command), and when I click on the button two things happen:

1. It creates an excel file on the server which is working just fine
2. I try to download it. That's the piece that is not working.

Here is my command slightly adapted to the post:

```
protected IReportService ReportService;
        public override void Execute(CommandContext context)
        {
            if (context == null)
            {
                Sitecore.Diagnostics.Log.Warn("Report not generated. The context is null", context);
                return;
            }

            try
            {                    
                Context.ClientPage.Start(this, "GenerateReport", context.Parameters);

            }
            catch (Exception ex)
            {
                Sitecore.Diagnostics.Log.Error("Error while generating the Excel report", ex, this);
            }
        }

        public void GenerateReport(ClientPipelineArgs args)
        {
            if (ReportService != null)
            {
                var list = ReportService.GetAssetsReport();

                var file = ExportToExcel(list);
                //The ExportToExcel returns a FileInfo object 
                Sitecore.Diagnostics.Log.Info("File name: "+ file.FullName, file);
                SheerResponse.Download(file.FullName);
            }
        }

```

If I get the value from file.FullName I see the absotule path to the file which exists on the server. If I copy this value and use it on windows explorer I see the file.
But the SheerResponse.Download will not download it.
Logs don't show any potential errors.
Any thoughts on what could be wrong?