After reviewing the problem, NYSE officials said trading would not resume on Wednesday and all trades that were not executed at that point will be considered cancelled.
The bell rang inexplicably at 3:56 p.m. EDT, prompting confusion on the trading floor.
The problem originated with the exchange's Securities Industry Automation Corporation, which disseminates market data and runs computer trading systems, a floor source said.
SIAC is a technology center jointly owned by NYSE and the American Stock Exchange.
A spokeswoman for the NYSE couldn't immediately provide details, but one trader noted difficulty getting orders filled.
"We have orders that didn't get executed," said Brian Williamson, vice president of equity trading at The Boston Co. Asset Management. "We heard from our brokers on the floor who were telling us that the system was essentially broken."
The NYSE is expected to open for trading at 9:30 a.m. Thursday, the exchange's standard opening time.