Some users are not seeing the checkbox reCAPTCHA widget, what's happening?

Good Day, Guys, I'm a noob on this CAPTCHA thing. I was at home and online...then I was asked to verify this CAPTCHA test but the checkbox was never there...it keep asking to do alternate tests......how do I resolve this? Looked at FAQs but couldn't understand what it was saying.... help please.... -- You received this message because you are subscribed to the Google Groups "reCAPTCHA" group. To unsubscribe from this group and stop receiving emails from it, send an email to recaptcha+unsubscribe@googlegroups.com. To post to this group, send email to recaptcha@googlegroups.com. Visit this group at http://bit.ly/1dkFnYd. For more options, visit http://bit.ly/P65DvS.