I have had a problem with kanger toptanks where they just stop working no matter what I do. They do not read on any mods and I have 4 mods I have tried them on. I have tried multiple coils including the different styles(occ-ssocc-rba). I have checked the pins and they are making contact. Mine was a toptank mini and my wife's did the same thing and it's a toptank nano. It's crazy that both are doing the same thing. If anyone has any other ideas please let me know