How to Troubleshoot a Possible Plugin or Theme Conflict
Debugging a plugin or theme conflict should be done on a staging site if possible.
1) Make a full backup of your site.
Make sure you have a recent full backup of your site (live or staging) and theme settings.
2) Deactivate all active plugins except for the plugin you're seeing the issue happen.
Deactivate all your plugins except for the plugin you're seeing the issue happen. If you have to do this on your live site, pick an off-peak time.
It's a good idea to select the active plugins filter near the top of the Plugins page and print that to a PDF file so you know which plugins to reactivate when you're done.
There's also a Health Check & Troubleshooting plugin that can help automate the turning off and on of all your plugins. But, it only works for the current logged-in user. That's great because only you will notice plugins going on and off. It's not so great if you need to log in as a different user to actually reproduce the error.
Note: If you have any custom code, you should probably deactivate those too.
What if you don't have admin access to your site?
Follow these instructions from wordpress.org if you can't log into your
3) Test for the error.
- Purge any server, database, and CDN cache.
- Open an incognito/private browser window. Incognito and private windows should start with a clean browser cache, no cookies, and no history.
4) Reactivate the plugins (from step 2) one by one.
You can start enabling plugins one by one until you see the JS errors come back in the console.
The last plugin you reactivated before you saw the JS errors come back is almost always the cause of the conflict. Let the plugin's author know.
5) Check for a theme conflict.
If the JS errors still show up with all plugins deactivated except for that 1 plugin from step 2, try switching your theme to a default WordPress theme (Twenty Twenty or Twenty Twenty-One, for example).
If the JS errors disappear after switching themes, then there's a theme conflict. Tell the theme's author or think about using a different theme.