Optimization plugins such as Autoptimize could break scripts like the jQuery script included in WordPress. That is what I see on your site. If jQuery's broken, all functions that rely on it like the submenu popup will be affected. Regretfully, we can't fix that as we do not cover support for website optimization issues. I recommend that you consult with a website optimization expert.
To give you an idea on optimization, we have a general optimization guide that you can read here: https://theme.co/apex/forum/t/customizations-performance/210
Please just take note of the disclaimer in that article:
Thank you for understanding.