(CNN) — American Airlines flights have resumed after a nationwide ground stop was issued for less than an hour Tuesday evening due to an IT outage, the airline said. “A technology issue briefly impacted connectivity for some of our systems on Tuesday evening. Systems are coming back online n ow and flights are departing again,” American Airlines said in a statement on X. While it was not immediately clear what caused the outage, the airline said a temporary ground stop was put in place while teams worked to resolve the issue. “We apologize to our customers for the inconvenience,” the airline said. The ground stop, issued around 6:30 p.m. ET, came during an unusually strong storm that is moving through the Northeast through Tuesday night and could drop more than a month’s worth of rain in parts of the region. More than 2,500 flights have been canceled at airports across the US, according to FlightAware. New York City’s airports are the most impacted, along with Newark Liberty International Airport in New Jersey. Thunderstorms forced ground stops at airports across major cities, including New York, Newark, Washington, DC, and Baltimore. American Airlines did not immediately respond to CNN’s request for comment. ...read more read less