Not ovulating, pls help

Hi all, 
​Pretty new to all of this so not sure of terminology etc. we've been trying to conceive since feb this year & still no luck. I've been taking the clear blue digital ovulation tests before during & after when glow tells me I'm fertile with still no luck, empty circle every time. Could there be a problem - I do get other signs though? I'm confused 
​Last cycle was 21st June - 26th June however 1 of those days was very light & 1 day nothing at all.