Captchas are used as a “Turing Test” to determine if an actual human is submitting the form instead of a bot or some automated process. These can be useful in minimizing spam, but if they need to be disabled site-wide, there is an easy way to do it.
From the Gutensite Control Panel, select the Admin tab, then Site Information → Technical. The last option on the page is a checkbox for disabling captchas. Check the box, then save the configuration. To re-enable captchas, simply un-check the box, then save the configuration again.