Since it's new I'm assuming the leak is at the juncture of the canister to the top portion and not a crack in the canister itself. The first thing I'd do is make sure it's on tight by using the canister wrench:
If that doesn't work I'd very lightly grease the o-ring with a silicone base lub....it can NOT be petroleum based. Plumber's grease is the common stuff as long as it's not petroleum based...comes in a small tube.