The Health Check & Troubleshooting plugin is made by the WordPress.org community.
It has a debug function that checks common configuration errors and known issues in a WordPress setup, and highlights them.
It doesn’t solve them, but it gives you the information to tackle the issue.
Theme and Plugin Conflicts
When you activate the Troubleshooting feature, it reverts your site to a default WordPress theme like Twenty Seventeen and deactivates all your plugins.
You can then turn your chosen theme back on to see whether the issue reasserts itself.
If it does then you know it’s a theme-specific issue.
If not, then you can re-activate your plugins one by one until you see the issue reappear. In that way you can resolve plugin conflict issues.
The neat part is that it does it only for you as the logged in admin. Anyone visiting the site sees your usual setup.
Take a full backup before you start…