A malfunction with computer systems at airports nationwide caused frustrated travelers to spend hours stuck customs lines.
The problem was with the Department of Homeland Security’s (DHS) system that checks passenger names against the country’s terror watch lists,according to NBC News.Complaints from customers began to pop up on Twitter at around 7 p.m. and officials told NBC News that the system went back up at about 9:06 p.m.
Affected airports thus far seem to be John F. Kennedy International Airport in New York, Boston’s Logan International, Hartsfield-Jackson International in Atlanta, Dallas Forth-Worth International, and Charlotte’s Douglas International Airport.
Tweets began pouring from passengers finding it impossible to get through customs, with no word from officials about what has caused the delay and whether there would be any relief soon.
The FAA, the New York Port Authority, and U.S. Customs & Border Protection Agency did not immediately respond to requests for comment; the New York Port Authority declined to comment.
This article is published in partnership with Time. It originally appeared on Time.com
For more about airports, watch this Fortune video: