The message occurs because rdesktop sends no authentication at the network level. This requirement can, however, turn off in Windows.
Control Panel -> System -> Remote settings
disable the option: Allow connection only from computers running Remote Desktop with Network Level Authentication (recommended).
توی سرور ویندوزی این کارو انجام بدید Network Level Authentication(غیر فعال کنید) تست کنید درست میشه