silentCAPTCHA AntiBot system warning message

If you use the silentCAPTCHA AntiBot system, you may have get the following warning under the Bots & IPs Zone > silentCAPTCHA:

"Important: Shield couldn't determine whether the silentCAPTCHA JS was loading correctly on your site."

Part of Shield's silentCAPTCHA involves the use of the NotBot Javascript snippet. This runs a small piece of code that helps Shield determine whether the current visitor is a human, or a bot.

So, ensuring this Javascript is present on your site is critical to the reliability of silentCAPTCHA.

When you load this options page, the plugin makes a quick HTTP request to your home page URL and checks to see if the NotBot Javascript file is present on the page. If it can't find it, it'll report the error.

If you don't see the warning message you can be very sure the NotBot JS file is loading, but if you do see the message, it could be a result of one of the following:

  1. The NotBot JS isn't being loaded
    1. this is most likely due to aggressive page caching rules
  2. Your IP Visitor Source option isn't set correctly
  3. Shield can't correctly determine your server IP address
  4. Your website is loading slowly (perhaps temporarily) and the page didn't load in-time for the test to complete
  5. Some sort of server configuration prevents the WordPress site from sending requests to itself
  6. Forceoff is in place

It's difficult to be sure which is the problem, but if your main goal is to determine whether NotBot JS is loading, here are some suggestions:

  • if you're using Page Caching:
    • try disabling page caching temporarily
    • re-run the test (i.e. load the options page)
    • if it works, try enabling page caching again and re-running the test
    • if it then fails again, you'll need to ensure your page caching is configured to allow all Javascript files to load correctly.
    • it can cause lots of troubles and we generally recommend not running page caching on WordPress. Here are 5 golden rules you can implement for your site optimisation. 
  • Check your visitor IP Source option is set correctly.

  • Check your server IP address that Shield has discovered for you.

    You can do this on the Debug Info page (under the Tools section) > Service IPs:



  • If you think your website is loading slowly, recheck again a bit later