my kids won't tell me about their day at school

i dont get it why they cant just talk to me like normal ppl do i mean they have a ton of stories but when i ask them what happened today all they say is nothing or that everything was fine. i try so hard to be interested and ask the right questions like did you learn anything new today? or tell me about your friends. it feels like im asking my kids to do something super complicated but then they just shut down. sometimes i feel like maybe i dont know how to be a good parent, that's probably it cause why else would they avoid telling me stuff. the other day i tried another tactic, i was like hey if you tell me one cool thing that happened at school imma let you stay up 10 more mins and now its been days and no results. im losing hope sometimes that anything will change.