Facing issue in uploading the file on FTP

Facing issue while uploading the file on FTP. Below is the code. private void UploadFileToFTP(string directoryName, string filename, byte[] bytes) { try { string ftpUserName = "username"; string ftpPassword = "password"; var requestUriString = "file pah on ftp"; var request = (FtpWebRequest)[login to view URL](requestUriString); [login to view URL] = [login to view URL]; [login to view URL] = new NetworkCredential(ftpUserName, ftpPassword); [login to view URL] = true; [login to view URL] = true; [login to view URL] = [login to view URL]; [login to view URL](); using (Stream requestStream = [login to view URL]()) { [login to view URL](bytes, 0, [login to view URL]); [login to view URL](); FtpWebResponse response = (FtpWebResponse)[login to view URL](); [login to view URL](); } } catch (Exception ex) { } } I am facing below crash.. The remote server returned an error: (550) File unavailable (e.g., file not found, no access).