This article explains how to customize the error message below, which is displayed when:

• Auth0.js is used to implement the login/signup screen
• And the library fails to load and present the Bot Detection UI

Error getting the bot detection challenge. Please contact the system administrator.

• Bot Detection
• CAPTCHA
• Auth0.js

The error message is hardcoded in the default template defined in the library's source code. Giving the language option (e.g., lang: 'ja') will not change/localize this error message.

The error function in the template option parameter has to be edited.

var captcha = webAuth.renderCaptcha(
  document.querySelector('.captcha-container'),
    {
      templates: {
        // IMPORTANT!
        // Customizing templates will overwrite the entire templates object. 
        // The template function for the successful path must be re-defined so that the Bot Detection in use keeps functioning even if no customization for this part is needed.
        auth0_v2: function () {
          return '<div class="auth0_v2" ></div><input type="hidden" name="captcha" />';
        },
        // Overwrite the error template.
        error: function() {
          return '<div class="error" style="color: red;">CUSTOMIZED/LOCALIZED MESSAGE</div>'; 
        }
      },
      lang: 'ja'
    },
  (error, payload) => {
    if (payload) {
      triggerCaptcha = payload.triggerCaptcha;
    }
  }
);

Related References

• renderCaptcha
• captcha