The
last time someone reported this issue (with a luxe, not a luxe 2) the person has inserted on of the batteries the wrong way, giving "battery error" on the screen. In most dual battery regulated mods, one battery goes positive up and the other positive down, making sure you have each one in the correct orientation. There should be "+" and "-" signs on the mod where you place the batteries.
If this isn't your problem, then clean both the + and - contacts on the mod very well and also clean the + and - contacts on the batteries very well.
very well....with rubbing alcohol.