Visual / Text Editor Not Showing

Recently migrated a site, everything on the front end works fine. however, when going to edit a page, the text is all in white so you can’t see it, and the tinymce (toolbar) isn’t showing at all. Can’t see anything in either the text or visual editor.

I’ve disabled all plugins, and switched to the default theme, but still have the same problem. Can anyone please offer some possible solutions?

Thanks,