PORTLAND, Ore. (KOIN) — Flights have resumed after a nationwide computer outage at the Federal Aviation Administration grounded all domestic flights.

The FAA ordered all U.S. flights to delay departures until 6 a.m. PST as it works to restore the system. Although officials are still investigating what caused the system outage, the FAA has lifted the ground stop.

The White House said there is no evidence of a cyberattack.

As of 6 a.m., there were more than 45 delayed flights into and out of Portland International Airport, according to FlyPDX. Eleven flights have been cancelled.

Dorothea Cooper, who is heading to Hawaii for her milestone birthday, told KOIN 6 that she thought there would be less trouble at the airport following the holidays.

“I wasn’t worried about it at all. I thought ‘oh, it’s after Christmas. There’s no ice storm except for the atmospheric river that’s going on.’ So, I thought ‘we’re Oregonians we can handle it, right.’ But then we got here and was like ‘okay, come on! We gotta leave on time.’ We’ll be a little bit late, but we’re still getting in.”

Cooper was told the flights delayed before hers will be taking off first.

Officials at PDX told KOIN 6 that “flights [are] operating as scheduled for the most part at this time.”

Stay with KOIN 6 for continuing coverage.