Leaking P trap

I just installed a new 1 1/2 P trap for a bathroom sink and its the type with the adjustable long arm with the securing nut on the top and I cant get it to stop leaking.

Any Ideas?

P Trap Leak

Make sure all the joints have the gaskets properly in place and that they are not torn or defective in any way. Tighten the joints good & tight. Check all the connections by dropping a full load of water down the drain. The leak may actually be from somewhere else, (above) and running down appearing on another fitting.