What does 'ships going dark' while crossing Strait of Hormuz mean?

Since July 8, two-thirds of ships crossing the Strait of Hormuz have gone dark amid the US-Iran war. "Going dark" does not necessarily mean that a vessel is operating illegally or secretly. It means that its exact route cannot be confirmed because of gaps in available tracking data, which can result from disabled transponders, jammed signals, or missing satellite imagery.