Classic Editor not working in WordPress 6.5 version

Hi there, can you please check if there are other plugins or themes that could be conflicting with the plugin?

This is likely caused by a conflict with another plugin.

How to test for conflicts

The best way to determine if the issue is being caused by a plugin is to:

1. Temporarily deactivate all plugins. You can do this manually or use a plugin to help (see below for tools).
2. Try to reproduce the problem. If the problem is resolved, it’s a plugin conflict. To figure out which plugin is causing the problem, continue to the next step.
3. Reactivate your other plugins one by one, testing after each, until you find the one causing conflict.

If this doesn’t help, you can try to change your theme temporary to see if it works as expected.

Recommended tools to help with troubleshooting

* Meks Quick Plugin Disabler will remember what plugins you had active when you switch it back on.
* You can clone your site to a staging environment and perform tests without modifying your live site or impacting customers. Many hosts provide staging facilities, so it’s worth checking in with them. It’s also possible to do it using the free WP Staging plugin.

I have seen similar behavior under PHP 8 and WP 6.5.2 on RHEL 8.9. I’m hoping my details can help find a thread to pull on.

If I set my host (I own and completely control my host, this is not a hosted environment) to use PHP 8, the text entry box will not take a cursor or any form of entry like copy/paste, and the Visual/Text tabs no longer work to flip between them. Basically nothing in the editor is functioning to get a post written. If I deactivate the plugin, the Block editor works, but my users despise it (which is why we use the Classic Editor).

I have completely rebuilt my site as a test environment using a completely empty database and no other plugins with the same results on PHP 8.1-8.3. If I revert to PHP 7.4.33 the Classic Editor again works precisely as expected — with no config changes other than removing PHP 8.x and reinstall PHP 7.4. I have had a number of issues with plugins under PHP 8.x and so have been trying to eliminate possible conflicts, looking at each plugin installed on its own in the test environment to rule out platform compatibility, so given I’m on an empty database with no other plugins installed and seeing this behavior, I’m convinced this is NOT a plugin conflict. It’s something to do with PHP 8 and RHEL 8 and how 6.5.2 functions on it.

I’ve not been able to find any error in a log related to this plugin, though I am seeing a number of warnings regarding undefined array keys in canonical.php under PHP 8, but I don’t think a warning would cause this.

@hockchas – I’ve been unable to recreate this when testing WP 5.6.3 with PHP 8.x active – Editor seems to work as expected for me.

It does sound like it might be something more specific to the particular setup you’re testing with.

Thank you @jordesign I forgot to come back and update this.

The issue for me ended up not actually being a plugin or WP config issue at all, it was an issue with certs and some replies from the web server coming back as not over https. It took opening the browser dev console to see that was the issue, as neither web server logs nor PHP logs were reporting anything being wrong.