WASHINGTON — An auction offering a 45-minute private meeting with Ivanka Trump in exchange for a charitable donation was abruptly canceled Friday after questions were raised about the process by ethics experts, who said it appeared to offer bidders special access to the next first family.

The auction had been running for 10 days, drawing 28 bids, the highest of which reached $72,888. The bidders included at least three businessmen who said in interviews that they saw their donation as an opportunity to have coffee with Ms. Trump to press her for information about her father’s plans as president or to try to urge Mr. Trump to take up an issue important to them.

All information on the amounts and names of the bidders disappeared from the internet with no notice on Friday afternoon. The winning bidder would have been an organization called Go Hydrogen, although no information could be found about this entity.