HttpRsponseMessage to Excel is succesful in Postmna but has no data

Question

I created method that aquires data and converts it to excel file.

result, file and fileContent are properly set and have values, however there is no attachment or data in Postman:

StatusCode: 200, ReasonPhrase: 'OK', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
{
Content-Length: 3866
Content-Type: application/octet-stream
Content-Disposition: attachment

[HttpPost]
        public async Task<HttpResponseMessage> GetAnniversaryTaskListReportAsync()
        {
            try
            {
                AnniversaryTaskManagementPanelSearchModel searchModel = new AnniversaryTaskManagementPanelSearchModel();
                string sheetName = "Report";
                var result = await _anniversaryTaskService.SearchRksAnniversaryTasksForManagementPanel(searchModel);
                var file = _reportService.ExportToXLS(searchModel, result, null, null, sheetName, true, null);
                var fileContent = file.GetFile();

                using (MemoryStream memoryStream = new MemoryStream(fileContent))
                {
                    HttpResponseMessage response = new HttpResponseMessage();
                    response.Content = new StreamContent(memoryStream);
                    response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
                    response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
                    {
                        FileName = "Test.xls"
                    };
                    return response;
                }
            }
            catch (Exception ex)
            {
                _logger.ErrorFormat(ex, "err GetAnniversaryTaskListReportAsync");
            }
            return null;
        }

Is there missing something ?

I need excel file or at least data to see that its properly working. Tried chatgpt and google