When trying to create or edit a custom booking form in the frontend of Matukio, the popup never loads.
The booking forms are working in the Joomla backend, they just cannot be edited or created in the Joomla frontend.
The attached screenshot gui_error.png (site details redacted) shows this issue.
This occurs both in Google Chrome 75.0.3770.142 (Official Build) (64-bit) as well as in Firefox 68.0 (64-bit).
The error has also been observed in Internet Explorer.
Both errors occur in the file main.min.js in line 26.
Can you reproduce this bug?