The Skyliner only opened on September 29, 2019, but less than a week later, on the night of October 5, the system had a pretty serious failure, and the line transporting guests to Epcot stopped moving. An unknown number of guests found themselves frozen in the air, and many of them spent more than three hours that way. Needless to say, that is not how anybody wants to spend any portion of their Disney vacation.
Article source: https://www.cinemablend.com/news/2482030/8-times-walt-disney-world-and-disneyland-attractions-went-really-wrong