A slew of stocks were briefly halted for trading on the New York Stock Exchange, shortly after the market opened on Tuesday.

Most of the stocks have resumed trading. NYSE did not immediately respond to a Reuters request for comment.

An update on the stock exchange’s website said all systems were operational after initial outage at the opening bell.

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“What appears to have happened is a technical glitch where all of my opening orders on the NYSE autocancelled even though some of them should have been fulfilled,” said Dennis Dick, trader at Triple D Trading.

“They have corrected that now but this is going to be a big mess to clean up.”