Wix uses a slightly different code to be able to show your website.
<html>
<body>
<script id="InnStyle-js" src="https://developer.innstyle.co.uk/calendar.min.js"></script>
<script>InnStyle('insertinnstyledomainnamehere');</script>
</body>
</html>
Your innstyledomain is often your property name, if you look at the URL when you are logged into your account it will show: propertyname.innstyle.co.uk, so just use your propertyname where it says insertinnstyledomainnamehere in the above code example