Can glow ovulation predictor be wrong ?

Darian
I've been ttc for four months now and I'd always baby danced in my fertile window and nothing happened. This month I decided to buy an ovulation kit and test it. Well glow says my ovulation days are spetember 19-25. However the ovulation test kept coming back negative on those days. I just took one today the 28th and it came back positive. Can glow be off?