Good morning,
Thank you for checking into this. I've included the site credentials. Also just realized, I can't modify my existing pages either. When I click on an article to modify it takes me to the screen to decide to use a joomla editor or SP Page builder, if I select SP Pagebuilder it takes me to the front to create a new page. So I am complete stuck at the moment on these sites.
I now have three sites doing this same thing.
I've several sites still running version 3.8.9 with no problems
Upgrade them to 4.0.6 and thats when it starts