CO2 cylinders for Sig MPX

Just bought my first airgun Sig MPX 0.177. The instruction recommends 90 Gram CO2 cylinder so I bought JT 90gram CO2 Tanks as well. Problem is after I screwed in the CO2 tank and pull the trigger, there is no pellet coming out despite a fully-loaded magazine. I checked the tank and it's pretty tight. Has anyone had similar experience? Any advice on troubleshooting is highly appreciated. Thanks!
 
the 88 and 90 gram tank are the same, at least they work in a Hammerli 850

look at the tank and see if the tip has a piercing pin mark on it if not i'm not sure 

i don't own a Sig but piecing a tank is fairly standard fair 

so if you take the tank out take a look up the butt end of the valve where the tank screws in an see if you can see a problem 

but again if it is pieced then the hammer is not striking the valve pin hard enough or again an unknown