During user registration (aka sign-up), an error is thrown: "Captcha text didn't match", but the captcha image doesn't render on my browser.
A CAPTCHA is a type of challenge-response test used to ensure that the response is generated by a person. The image itself can be blocked in many ways, so if you run into the case where your browser isn't rendering the captcha image, you can check any of adblocker extensions and/or site blocker extensions and settings.
The examples we've come across is where Safari won't display the captcha image specifically when Incognito (by Orbicule) is installed. To render the captcha image, go to Safari->Preferences->Extensions and select the Incognito extension. Uncheck "Google APIs", then refresh the browser page - the image should appear.
There are other examples when Googling "captcha image not showing up".