I had similar problem when registering last month. I was running Firefox with ad blocker add-on, and I kept getting rejected on the questionnaire, even if the answer were correct. I know my Firefox had been having issues on other websites lately, so I switched to Chrome and tried again. By then, I noticed there was a captcha / 'I'm not a robot' verification thingy that wasn't there during Firefox session. I guess my Firefox adblock may have blocked it. I don't have any add-on on Chrome since I barely use this browser. So after I checked this "I'm not a robot" box, the registration got accepted right away.
