Have you checked the pin on your mod? They use a spring loaded center pin to transfer the current. Sometimes those pins can get stuck. Take some kind of pokey thing and push it down, it should be firm but have some give. If it's not pushing down it might be stuck in the down position, so try and wiggle it around a little and see if it pops up some. Maybe try measuring the distance down to that pin and the length of your atomizers connection, the atomizers connection should be a tad longer.
Another option, if you have a friend with their own mod, or if there is a vape shop you frequent maybe you can get someone to let you try using it on their mod, see if it works and maybe it's just your mod that's a bit messed up.
Problem with mass production is sometimes there's flaws and sometimes they get past quality control. Often they'll still work, but just not perfectly so that could be it, that the pin on your mod is just slightly too short, or the opposite and your tank is slightly too short so it's not making a solid connection with the mod.