Board Thread:Support Requests - Getting Technical/@comment-26111629-20190622191906/@comment-9605025-20190624043801

In that case, try changing it to the classic editor (rich-text editor for visual and source mode; source editor for source mode only) and see if that helps. If it is currently set to VisualEditor, then the default is it tries to open VisualEditor, which can be buggy.