はず vs. べき
I was writing a (business) email and went to write the following sentence: “Maybe I’m just not seeing some button that I’m supposed to click on.” もしかして私がクリックするべきボタンを見ていないかもしれません。
For some reason はず sounds wrong there (to me). They’re both grammatically correct (can be used after short-form verbs). I think it’s because hazu expresses an expectation, and beki expresses an action that should be done. I don’t need to emphasize someone expecting me to click a button, so I can detach and say ‘the button that [I] should press”.













