We have discovered that the SiteGround Optimizer plugin causes some serious compatibility issues on the front-end of WordPress websites, in particular with Shield Security.
This eventually leads to IP addresses being blocked.
The options within the SG Optimizer plugin that cause issues are:
- Defer Render-blocking JS, and
- Remove Query Strings From Static Resources
If you go to the SG Optimizer plugin settings and review the Frontend options, try disabling the option to "Defer Render-blocking JS" and then enabling it again. You'll see that you're presented with a big warning that says it can break the site. But it appears that this warning is going unheeded for many people and is causing some strife.To mitigate this, we have now built-in protection into Shield to prevent this conflict causing trouble further down-the-line.
The WordPress admin page will present the notice with a link to automatically disable the SG Optimizer options that cause the conflict.