Unable to edit: TypeError thrown

This problem may be a plugin or theme conflict. Please attempt to deactivate all plugins and switch to the default Twenty Twenty-Two theme. If the problem goes away, re-activate them one by one to identify the source of the problem.

If you can install plugins, install Health Check. On the troubleshooting tab, you can click the button to deactivate all plugins and change the theme for you while you’re still logged in without affecting normal visitors to your site.

James,

The health check plugin is only compatible up to WP 6.3.2. Furthermore, the support forum for it indicates that it is unreliable.

Also, I thought Twenty Twenty-Four was the default theme for WordPress 6.4.x. Why do you want me to install Twenty Twenty-Two?

Someone must have forgotten to update Health Check’s supported version, I’ll let them know.

It works find under 6.4.2, but if you’re uncomfortable, you can do the troubleshooting steps manually as mentioned.

Technically, all of the Twenty themes are defaults and solid for troubleshooting, but to be on the safe side, I like to hang a version or two back on that. You can use Twenty Twenty-Four if you want.

It appears to be a browser issue. I was able to create a new page using Firefox. I was having issues with Chrome.

Excellent! I’m not having any issues with Chrome myself, so I’d start by ruling out the browser extensions similar to the plugins.

Disable all Chrome extensions and re-activate them one by one until you find the one causing the problem.

Make sure you include any ad/tracker blockers too, sometimes they can get a bit overzealous and block things that are neither ads nor trackers.