//Downdload file
    [HttpPost("download")]
    public async Task<IActionResult> DownloadFile([FromBody] FileUpload Upload)
    {
        Config.DefaultResponse response = new Config.DefaultResponse();
        try
        {
            string siteUrl = "";
            var RelativeFilePath = "/sites/YourSiteName/YourLibraryName" + Upload.FolderName + "/" + Upload.FileName;
            var apiUrl = $"{siteUrl}/_api/web/GetFileByServerRelativePath(decodedurl='{RelativeFilePath}')/$value";

            var accessTokenResult = await GetAccessToken();

            if (accessTokenResult is ObjectResult accessTokenObjectResult && accessTokenObjectResult.Value is string accessToken)
            {
                using (var httpClient = new HttpClient())
                {
                    httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
                    httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                    var downloadResponse = await httpClient.GetAsync(apiUrl);
                    var responseText = downloadResponse.Content.ReadAsStringAsync();

                    if (downloadResponse.IsSuccessStatusCode)
                    {
                        var filecontent = await downloadResponse.Content.ReadAsByteArrayAsync();
                        return Ok(filecontent);
                    }
                    else
                    {
                         
                        response = new Config.DefaultResponse(500, "Failed to download", responseText);
                        return BadRequest(response);
                    }

                }

            }
            else
            {
                response = new Config.DefaultResponse(500, "Failed", "Something Wrong occured");
                return BadRequest(response);
            }
        }
        catch
        {
            response = new Config.DefaultResponse(500, "Failed", "Something Wrong occured");
            return BadRequest(response);
        }
    }