Resnexus Booking Widget

Hi, we currently use the platform Resnexus, and have their widget embed on a test page. 

https://www.thevineyardathighholly.com/test-widget

We are unable to get the calendar function to work when clicking. The code works in a test environment when I upload it outside of Squarespace, but when I load it on Squarespace, the small calendar doesn't show up when clicked. 

Anyone had a problem with embedding widgets? Uploaded what it should look like in the test and what it does when I try to click the calendar button on Squarespace. 

Thank you for any ideas! 

You can use this code to Website > Website Tools > Custom CSS to fix problem

[data-section-id="660f448e993fc551ebf12ed2"] {
    z-index: 123456789 !important;
}