What are your qualifications?
This is the fallacy of arguing that if someone has not received formal education in a particular topic, he or she is not allowed to present criticisms on that topic of interest. It is essentially an ad hominem attack and a defence of their view by an argument from authority.
This question represents a fallacy because information is legitimate or illegitimate regardless of whether the individual reporting it is an expert or authority. Although an expert likely knows more about a given subject, may be more likely to be correct unfounded assertions, and may be more believable, information itself does not rely on an authority for its legitimacy. Therefore, whether an individual is presenting valid criticisms of an idea depends not on his or her qualifications, but on his or her information and reasoning.