I have set up a demo site for you to debug on. let me know if there is anything else you need.
Not really as this is a local development site. I'll see about deploying it somewhere for you to test.
In the meantime I'll try reinstalling the Metabox plugin.
I should add that we are using the classic editor and WP 4.9.8. No other plugins are installed.
Hi
Sorry for taking so long to reply, I've been on another project. This is the output:
TypeError: textarea is undefined[Learn More] editor.js:100:5 switchEditor http://localhost/wp-admin/js/editor.js:100:5 init/< http://localhost/wp-admin/js/editor.js:34:7 C http://localhost/wp-includes/js/tinymce/tinymce.min.js:2:11105 d http://localhost/wp-includes/js/tinymce/tinymce.min.js:2:11256
Any ideas?