"All systems go" is a phrase that refers to everything being ready to go or proceeding as planned. Antonyms for this phrase could include "all systems stop" or "all systems fail," indicating that something has gone wrong and progress has come to a halt. Another antonym might be "all systems slow," implying that while progress is being made, it is happening at a much slower pace than expected. Other antonyms could include "all systems disconnected," "all systems delayed," or "all systems out of order." These words all suggest that the normal functioning of processes has been interrupted or inhibited, creating a state of disorder or stagnation.