z-index on modalplate-overlay and modalplate not working

I’m not sure why this is happening but the modalplate is behind the modalplate-overlay div

https://timothyfullerarchitects.com/newtest/guide/

I’ve tried changing the z-index on one and both elements, and changing the opacity. I’ve had this plugin work a different site just fine.

I’ve tried turning off all the plugins and it still doesn’t work. Do you have any suggestions?

Thank you!!

https://www.ads-software.com/plugins/wp-modalplate/