expression, godan verb (-u)
go wrong; go awry; go off track
Idiomatic expression literally meaning 'the gears go out of sync'; used figuratively for plans, systems, or situations that stop working smoothly.
See also: 狂う
計画の歯車が狂い始めた。
The plan started to go awry.
ちょっとした誤解で、すべての歯車が狂ってしまった。
A small misunderstanding threw everything out of whack.