A leak in the hydrogen tank of the Artemis I Moon mission led to the statement.
Attempts to get it off Earth were hampered on Monday by a mix of technical and weather difficulties.
The leak on Saturday was discovered as the rocket’s super-cold propellants were being loaded.
The fixes tried by the controllers were all unsuccessful.
The spacecraft uses 2.7 million liters of liquid hydrogen and oxygen to burn in order to generate the thrust required to leave the planet.
However, an alert went out, signaling there was a leak, when the controllers transmitted the order to fill the hydrogen tank.
The problem is at the base of the Space Launch System, at the interface where a 20cm umbilical line brings in the hydrogen.
Saturday’s attempt to dispatch the Space Launch System (SLS) rocket had been scheduled for the start of a two-hour window beginning at 14:17 local time (19:17 BST; 18:17 GMT).
The 100m-tall vehicle’s objective was to hurl a human-rated capsule in the direction of the Moon, something that hasn’t happened since Project Apollo ended in 1972.
Monday’s bid to fly SLS was ultimately scrubbed because controllers couldn’t be sure the four big engines under the rocket’s core-stage were properly prepared for flight.
The shuttle-era power units are chilled during countdown to -250C to prevent them being shocked by the sudden injection of cryogenic propellants at the moment of launch. But a sensor was indicating that Engine No 3 might be 15-30 degrees short of where its temperature needed to be.
When the SLS does get away, it is sure to be a spectacular sight.
“It’s gonna be ‘shuttle on steroids’,” said Doug Hurley, who was the pilot on the very last shuttle mission in 2011.
The former astronaut now works for Northrop Grumman who make the big white solid boosters on the sides of the SLS.
“What I always thought was the coolest thing about shuttle launches was you saw it lift off and it was well clear of the tower before you heard anything, and then it was even a little longer before you felt it,” he explained.
“Thrust to weight-wise, SLS is pretty close to what shuttle was. Apollo’s Saturn V rocket was drastically different. I never saw it in person but it lumbered clear of the pad. For shuttle, it seemed like it was clear in an instant, almost as soon as the boosters were lit. SLS should be the same,” he told news reporters.
The first powered phase of the SLS’s ascent will last just over eight minutes.
This will put the upper-stage of the rocket, with the Orion capsule still attached, into a highly elliptical orbit that would see the two of them come crashing back to Earth without any further effort.
So, the upper-stage will have to raise and circularise the orbit before then boosting Orion in the direction of the Moon.
Two hours and five minutes after launch, confirmation that the capsule is on its own, on course, and traveling through space at a speed of 30,000 km/h (19,000 mph) is expected.
The mission is expected to last little about 38 days. Orion would return to Earth as a result, splashing down in the water off San Diego, California, on October 11.
The maximum amount of time that astronauts should spend in the spacecraft, according to capsule builder Lockheed Martin, is 21 days, so 38 days is a significant increase.
But according to Annette Hasbrook, a senior advisor on NASA’s Orion program, engineers wanted to push the spacecraft to its limits on this voyage.