Answer:
Even though Andrew Jackson won the most electoral and popular votes, he didn't win by enough to beat any of the other three candidates. This meant that the final vote was up to the House of Representatives. Henry Clay, with the least amount of votes, knew that neither himself or Crawford would win and he hated Andrew Jackson, so he turned his votes over to John Adams which gave Adams the most votes and made Adams win.
In 1828, Jackson beat his other candidates and won the presidency.