American Airlines requested a nationwide ground stop, which was later canceled, on the morning of Christmas Eve due to technical problems.

American Airlines said on Tuesday its flights had resumed after a technical glitch forced the carrier to issue an hour-long ground stop, disrupting travel for thousands on Christmas Eve, one of the busiest periods of the year.

Following a brief outage that grounded all American airlines flights during one of the busiest travel periods of the year, American Airlines says it has resumed service Tuesday morning. American Airlines said a “vendor technology issue” was responsible for delaying all of its flights in the United States.