MixItUp Filtering: Uncaught TypeError

I’ve been trying to implement multi-dimensional filtering on my site using Mix It Up.

I keep getting an error from the browser saying:
Uncaught TypeError: [MixitUp] Invalid configuration object property “multifilter”

it’s related to line 53 of the custom code included in my page which you can see here:

Here is my public share link: Relief Watch – Demo

Here is a read-only link for the project: https://preview.webflow.com/preview/reliefwatch?utm_medium=preview_link&utm_source=designer&utm_content=reliefwatch&preview=1f8c354f55bb60e7d2919a43e7a40e2b&pageId=5d7635cb6f4ae1d09e6e0d18&mode=preview

Any help or assistance from anybody familiar with Mix It Up would be most appreciated!

Thanks