I installed some security packages a while back and noticed that HTML view in the WYSIWYG editor is not working. When I click HTML in the editor a blank window pops up and that is all that happens. Is there a file or something that controls this. I am using 184.108.40.206. I have a screenshot showing the issue below.
Unfortunately, I can't see your screenshot. However, I had a similar issue. It turned out that Firefox did a security update and I was unable to view the WYSIWYG editor as well. I tried Edge and had other issues. Currently the only browser that is supporting most functions of the admin for me is Chrome.
Not sure if this will help.