Need some help with batteries

[Dlkingfisher]

Hey LPF members I need some advice on a situation I'm having with my batteries for my cooper dominator by blood. Im able to run it fine when I stack two 18650 button tops, however when I try the same thing with 26650 button tops I'm having an issue with not getting power to the laser. It seems that they aren't making a good enough contact between the batteries but I could be mistaken. Does anyone have any advice as to what I should do?
These are the batteries I am having an issue with.
I'm able to stack an 18650 on top of one of these and get power to the laser but not when stacking two of the same