Widgets can be added to your WordPress installation by the WordPress core, plugins, or themes. If you add a widget to a page and then remove the plugin or theme that provided that widget, the widget will show as missing. Try following the below steps to resolve the problem:
1. Start by going to PluginsSiteOrigin Widgets. The SiteOrigin Widgets Bundle and third-party plugins (e.g., Widgets for SiteOrigin and Livemesh SiteOrigin Widgets) that make use of the Widgets Bundle framework will add their widgets to this page. A plugin can be activated, but if the widget you need isn’t activated, it’ll show as missing.
2. If the missing widget can’t be found at PluginsSiteOrigin Widgets, go back to the page you’re editing. Below the Missing Widget notification will be the widget name or ID. Hopefully, you will be able to find out which plugin or theme provided the widget and then investigate whether that plugin or theme is deactivated.
If you see a 404 error when editing SiteOrigin widgets, please reach out to your hosting company. Let them know you’ve been experiencing 404 errors when editing widgets in your WordPress site, and you believe ModSecurity could be the cause. Your hosting company will then be able to review their ModSecurity logs and, hopefully, adjust their rules to account for the false positives.
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.