Navigation bar not working properly

Hi everyone, our website navigation bar isn’t responding. We’ve been making changes for a while but in the past month we’ve experienced an issue with the navigation bar only appearing when we scroll down and it not being clickable. We’ve tried rolling back but for some reason that doesn’t seem to resolve the issue. Please see link below. Any suggestions/advice gratefully received. Thanks.

https://preview.webflow.com/preview/danieljohnsonxyz?utm_medium=preview_link&utm_source=designer&utm_content=danieljohnsonxyz&preview=2b73afd629bd2dcedbfebe9658cbedff&workflow=preview