I'm trying to add a widget (Flex Mag: Ad Widget) to add a widget to a widget area (Post/Page Sidebar Widget Area).
Selecting the widget and entering the required info works as intended, however, when clicking save I'm immediately bounced to a 403 Forbidden page and nothing is saved.
Error: 403 Forbidden Access to this resource on the server is denied!
The only thing I can see that may be causing the error is Defender's 'Prevent PHP execution' security tweak.
I have tried reverting the fix, which doesn't seem to work, and deactivating Defender completely.
Also, when attempting to add the same ad code into Appearance / Flex Mag Options / Article Settings the save button perpetually spins and nothing is saved.
I've tried all the standard using several browsers, computers, internet connections cache empty, disabling other plugins etc.
I've not noticed any other abnormalities across the site.