Challenge? Sue her financial organizers. They're collecting money for a known fraud. Every credit card transaction for a donation, every solicitation for campaign work is all aiding and abetting a fraud.
One of her earliest arguments would be there is no basis for finding a fraud, that the entire United States Congress formally considered the matter in a Joint Session convened solely for the question and dismissed any eligibility fraud.
(Partial hat tip to Madam Pelosi, Rino's et al.)