This happened to me once, i was so upset about it. I make sure if i do any of the FC surveys to make sure they are the 5 minute ones, so im not stuck spending half an hour on something that will disqualify me for no apparent reason. I recall getting disqualified after i selected my gender one time, i thought to myself, how discriminatory! anyway, i avoid surveys these days for that reason! :-
If a particular survey's demographic criteria calls for a different gender than the one selected, how is this "discriminatory"? What if they were vetting for
female survey-takers because the male respondants had filled that particular criteria quota; would that be "discriminatory" to male survey-takers?
Failing to qualify, (getting Dq'd), from any one survey depends on what may have 'gone wrong'. The possibilities include, (but are not restricted to); rushing through a survey, providing inconsistent answers, being disqualified under demographic criteria, not clearing "cookies" before taking a survey, having a survey's demographic-quota parameters fill while taking the survey, or not leaving the completed survey/"congratulations" page up for 5-10 minutes. Many of those things happened to most who've taken surveys before and they used to happen to me as well when learning the ropes. Evenso, sometimes 'glitch happens'.
Welcome to FC, doubtless you'll get the hang of it - don't forget to enjoy the site while making money.