Fatal error: Cannot find a library with slug debugger

Hi there,

Where exactly are you seeing this error? Is it a pop-up that appears on the screen, or does that appear on the screen instead of the Customizer loading?

Do you also get the error if you go to Appearance ->Customize, and then select Additional CSS from there?

I don’t see the error following the same steps with the same version of Jetpack and WordPress, so my first guess would be a plugin or theme conflict on your site.

Please try disabling all plugins except Jetpack and switch to a default theme like Twenty Nineteen to see if that helps. If it does, re-enable things one at a time until you start getting the error again to narrow down what is causing it.

The error only appears when I go to Appearance ->Customize and select Additional CSS.

I’ve disabled all plugins with the exception of Jetpack and the problem goes away. I’ll find out which one’s causing the problem.

Thanks for your help.

I found the one that’s causing the problem, but I have no problems with it since last updating it over a month ago?

Given the timing, I wonder if WordPress’s own update to 5.2.1 two days ago introduced a conflict with the other plugin. As Jetpack hasn’t had a new release since then, I don’t think it’s a conflict introduced from Jetpack’s end.

What is the other plugin? Can you try contacting that plugin’s support so they can also try looking into this from their end?

The problem was linked to a mobile theme plugin. I’ve disabled the plugin and switched to using Jetpack’s mobile theme.

Thanks for letting me know ??