I don’t know about you but I try to update my sites to the latest version of WordPress as soon as possible. In most cases, nothing breaks after an update. After upgrading to WordPress 5.5, Classic Editor stopped working on a couple of my sites. One way to diagnose this issue is by disabling custom themes and plugins. In most case, this problem arises from a code conflict. Enable jQuery Migrate Helper is just the plugin you can use to solve some of these issues.
This plugin is not meant to be a permanent solution, but it gives you more time to find a solution to problems in your code. In our case, we got the message “jQuery.fn.live() is deprecated.” It is an easy fix as you can simply use the .on() method instead. After this simple fix, Classic Editor started working again. The best approach is to always have the latest version of the theme and plugins you have adopted to avoid these problems.