ovulating on birth control?

So I've always thought that birth control pills stop you from ovulating, I recently moved to the flo app and noticed even though I marked I'm on birth control it still says I'm ovulating and high chance to get pregnant, i've been on the pill for while and never really worried about that? but that i see it on the app makes me scared to have sex? just confused. obviously i haven't gotten pregnant and haven't worried about ovulating? why does it say that?