the remote server returned an error: (550) File unavailable (e.g., file not found, no access).

I am trying to check if folder not exists then create on ftp but I am keep getting this error  he remote server returned an error: (550) File unavailable (e.g., file not found, no access).

I check permission on ftp the folder has permiss read and write etc.. and i checked the directoryPath
   public static void FtpCreateDirectoryIfNotExists(string directoryPath)         {             try             {                            WebRequest request = WebRequest.Create(directoryPath);                 request.Method = WebRequestMethods.Ftp.M ...