How come john quincy adams did not get reelected

John Quincy Adams died before he can run for a second term. 

John Adams failed to obtain a second term because of how poorly his first term went. He passed some controversial laws and even declared the "Quasi War", an undeclared naval war with France. He was also facing Thomas Jefferson, a very popular candidate at the time. It was kind of like comparing Bush and Obama, in terms of where they sat popularity wise.