OPK Result Question...

So, I’d used an opk for the past few months with no problem. However, I didn’t use one for my last 2 cycles as my SO and I wouldn’t be near each other. I just started again but with a new digital test reader since my other one wasn’t working. Now I am getting nothing but low results (just the circle with no smiley) on the Clearblue Advanced. Is it possible that it just has not adapted to me yet?? I’m testing exactly like I have on my previous packs. Any input ladies?? I’m with my SO while in my predicted fertile window so anything you got hit me with it!!