For anyone having issue with their SB, this might help: "You most likely crushed the insulator with that adapter. Thread your 901 onto the adapter all the way. Now look at the center post of the adapter. The insulators in the 510 connectors are only 1mm thick. I bet you that after installing the 901 onto the adapter, the center post sticks out close to a 1mm. What do you think happens to the insulator when you thread the adapter onto the SB. You may only tighten it lightly when installed. You can try to lightly pry the center post up a bit to make contact with the 510 atomizer again."