Mobile Menu Drop Down Broken

I had the same problem and I had to switch of Java script optimize in Autoptimize plus I had issues with contact form 7 so switched off Amp for that page.

excluding assets/js/navigation.js from JS optimization should suffice to fix issues with the mobile menu & Autoptimize really ??

The dropdown menu on mobile phones stopped working on my WordPress site.
I am using the Twenty Seventeen Theme and it is updated. All my plugins are updated.

The site where the drop down is not working is lchf-rd.com.

Can you please help! This is urgent as most of my business is generated from mobile phones. Thanks!