The date outputting when you open a widget is a common sign that Wordfence, for whatever reason, has incorrectly flagged the request. To resolve this please navigate to WP AdminWordfenceTools and open the Live Traffic tab. Filter by Blocked by Firewall and search the request you just made, it’ll be associated with your user account and the parm will start with body: instance=%7B%22frames%22%3A%5B%7B%22content. Click Whitelist param from Firewall.
If Wordfence doesn’t show the blocked request in the Live Traffic tab, you’ll need to put Wordfence into Learning Mode and then repeat the action to trigger the Block. Wordfence won’t block the request this time and you can now disable Safe Mode as it’ll remember not to block this request.