A cabin fire during a launch rehearsal test on January 27 at Cape Kennedy Air Force Station Launch Complex 34 killed all three crew members—Command Pilot Virgil I. "Gus" Grissom, Senior Pilot Edward H. White II, and Pilot Roger B. Chaffee—and destroyed the Command Module (CM). The name Apollo 1, chosen by the crew, was officially retired by NASA in commemoration of them on April 24, 1967.
https://en.wikipedia.org/wiki/Apollo_1
Arguably not a launch, as it was a rehearsal.