The contact owns a Cybex Safety Seat, Model Type: Eternis S, Model Number: 518002873, and was Manufactured on February 28, 2021. The contact stated that while attempting to secure the child into the car seat, one of the two shoulder harnesses connected to the rear of the car seat detached, and the child could no longer be secured in the car seat. The cause of the failure was not determined. The manufacturer was notified of the failure. No further information was available.