Failed to load plugin url….otw_shortcode_tinymce_plugin.js

When editing a page or post a pop up has started to appear: –

Failed to load plugin url: https://finegolf.co.uk/wp-content/plugins/widgetize-pages-light/include/otw_components/otw_shortcode//js/otw_shortcode_tinymce_plugin.js

Looking at a previous support topic this seems to be a conflict with the gutenberg editor, However this site already uses the Classic Editor plugin which solved the problem for other people but not for us.

The Widgetize plugin seems to be working fine on the front end so how do I resolve this issue?