When I try to shoot while using scope, it doesn’t fire. In creative mode, I could. What should I do?

Send your modpack. Works fine when I test

I've found its cause! I had a shield on left hand, and then I can't shoot with using scope. when I have crossbow on left hand, the same occurred. Sorry for bothering you by my stupid question.

hrt_cgm.zip
here's my modpack I downloaded on your website.