Try inspecting the threads to see if they are damaged. Also if the positive pin is down to far that can interfere with the threads. I has a vivi nova from FT that would not connect to my battery's until I shortened the positive pin, it bottomed out before any threads would catch. I don't have a I Atty but if it is built like most other genny style atomizers the positive pin should be adjustable. Can you post a pic of the threads?