I use and talk about, but don't sell Amsoil.
Who is shatto?
06 4.7 Tundra replaced a 98 Dakota 3.9.
623,000 miles on original engine and transmission, using Amsoil by-pass filters and lubrication.
+Everybody knows something you don't know.
+Artists prove truth can be in forms you don't understand.
Low-Risk Option Trader
Retired Pro-Hunter featured in; 'African Hunter', by James R. Mellon III. and listed in; Rowland Ward's Records of Big Game.
I'd say it looks like you got a leak there. You can buy an assorted pack of O rings for a/c systems at most auto parts stores for about $6. Make sure you buy the green ones. The black ones don't hold up as well. If you can get a hold of it, Loctite makes a special form of Loctite to seal refrigeration systems. I usually put a thin film on the mating surfaces as an extra assurance that its sealed, and I'm good.
Depending on the age of the vehicle, you may want to consider taking all the freon fittings apart and replacing the O rings, and sealing it back up. Make sure you hook it to a vacuum pump and vacuum it out to boil off any water left in the system before you refill it with Freon.
EDIT: Be sure to clean the oil residue off that fitting with some brake or carb cleaner so you can tell if it starts to leak again in the future.