That happens when you solve many ReCaptchas. Google detects that and doesn't show new ReCaptcha to you.
Google don't like that people are solving ReCaptcha and earn money for that. Sometimes they show you that error message or even ban your IP.
Try to configure your software as shown on this page. If that doesn't help then you got to wait until your IP will be unbanned.
Unfortunately we can't help you with that issue so there's no need to contact us on that matter.