leaking waste outlet

[henkrosa@hotmail.com]

hi
Please,does anyone have suggestions about how to seal the waste outlet on a ceramic sink.Can't seem to cure a leak between the rim and the flanged nut of the chrome threaded outlet.Nightmare,and the thread itself leaks through the nut.So?silicone,teflon tape.I've tried several things,but am not there yet.
Appreciate your comments.regards henk