Ok so I have this same issue going with my cool fire , I had dropped my eleaf 50 a few months back and broke the screen so I went to my second mod , my cool fire 4 I put on my subtank plus and boom check atomizer ...put tank on other mods at friends house and no issues , so I bought a subbox kit and put tank on cool fire , no issue , placed subtank on subbox , no issue . Since then I have bought a couple more mods and tanks and none of my other tanks gives this error just my subtank plus , I bought a new airflow base , replace the pin and insulator and changed the coils various times ....no dice , so I am stuck using my subtank on my other mods as it refuses to work on cool fire .this has been a stand up mod for me for almost a year and no issues except the pesky subtank thing . Not sure what it is but I feel your pain