PLG_SYSTEM_RSFPRECAPTCHAV3_browser_error

The Error

Why am I seeing this error when using reCAPTCHA V3 for RSForm! Pro?

This is actually caused by the fact that you are running Joomla! 3 and it's loading the MooTools library through mootools-core.js and mootools-more.js

The Solution

RSForm!Pro does not load MooTools, you will need to either:

• disable MooTools from being loaded on your page. MooTools is not an extension that you can uninstall - it's part of the Joomla! 3 code (framework) and can be loaded by other extensions on your website (eg. a component, a module, the template or a plugin). The Joomla! forum has some tips on how to prevent MooTools from being loaded either by using a 3rd party extension or by manually editing the Joomla! 3 source files.
• update to a more recent version of Joomla! (MooTools has been removed since Joomla! 4) - a full backup is firstly recommended
• switch to another captcha field:
  • you can check the HashCash Honeypot field here
  • you can take a look at other RSForm!Pro antispam plugins here (note that not all of these are free)

The Side Note

This MooTools library already have issues with the Google Maps Javascript API so it's safe to say it's most likely the cause of this reCAPTCHA issue as well.

The "browser-error" string is not defined by the Google reCAPTCHA docs, you can read more about this here.