WordPress 5.8 widget not working
Since WordPress 5.8 update, start showing blocks in all Widgets. If you notice a change in widget area appearance. In some websites, the widgets will not display or will load slowly. Below is how to fix the widget problem after upgrade to WordPress 5.8.
Fixing WordPress 5.8 widget not working
1. Switch to the default WordPress theme
The permanent solution to this problem is to switch to the default WordPress theme and check if you are still experiencing the problem. If there is no problem with the new widget area after theme switch, then your theme is the cause of the problem.
If the problem is not in the theme. then deactivate all plugins. Enable each plugin one by one and check whether the problem is solved.
2. Classic Widgets plugin
A Temporary fix is that you can use classic widget plugin,until you familiarize yourself with new block widgets.
Additional WordPress 5.8 widget not working
When trying to edit widgets that used the “Custom HTML” widget box, I’m getting the “Potentially unsafe Operation” warning, but it won’t let me click the check box to continue anyways. There was no problem before the new WordPress 5.8 Widget “Block Editor” function. Somehow this function is conflicting with the WordFence’s detection.
From the Wordfence Dashboard click on “Manage WAF”. Then you will see “Basic Firewall Options > Web Application Firewall Status”. Change the option to “Learning Mode”. Now perform the actions such as page loads or edits that were causing issues. This will help Wordfence learn that these actions are normal and it will allow them in the future. After you have finished performing the actions, switch the WAF from Learning Mode back to “Enabled and Protecting”. Now after these actions, it will work correctly and properly.