Why can't I use the e-gate when leaving Thailand on a Non-O visa?

Little bit of trivial for you im on a non o i work FIFO so I fly to Thailand every month so I fly back with jet star so every time i go to use the e gate to leave it wont let me through so i have to go to the immigration officer to check out i thought it was my passport as it's old but the immigration officer informed me because i check in online and not go to the counter it's not letting me through..anyone else have this problem