DENVER INTERNATIONAL AIRPORT, Colo. (KDVR) — A computer failure at the Federal Aviation Administration caused thousands of flights to be grounded across the country including those out of the Denver International Airport.

According to the FAA, the administration was working to restore its Notice to Air Missions Systems. Operations across the National Airspace System are affected.

The NOTAM system sends out important real-time flight hazards and restrictions to all pilots. Due to the system being down, many airlines are temporarily delaying all domestic flights.

At 6:50 a.m., the FAA reported that air traffic operations are resuming as normal.

The administration was working to perform final validation checks and to repopulate its computer system in order to get it back up and running.

“It’s absolutely critical to the safety of the flight so when that system (Notice To Air Missions) goes out of service, we see what we saw this morning the system shuts down because pilots need that information,” MSU Denver Aviation Professor Jeff Price said.

Worth noting that this outage was broader than just commercial airlines. All users of the airspace system are required to check Morand before flight. This affected military, civilian drone pilots, etc.

President Biden has been briefed on the issue and said there is no evidence of a cyberattack.

At the peak of the outage, out at DIA, there were 310 delays and 42 cancellations, according to FlightAware. DIA said that no domestic departures were flown out of the airport since 5 a.m.

“I was hanging out in the lounge and then they made an announcement the FAA grounded all planes until 9 a.m.,” passenger Brad Rayborn said. “I thought today is going to be an interesting day.”

FlightAware was also reporting that there were 3,578 total delays within the U.S. as of 6:17 a.m.

“Everybody has concerns especially the airlines because you don’t know what’s going on and the passengers have no idea and they couldn’t tell us because they didn’t know,” passenger Ros Druffel said.

The agency continues to look into what caused the initial outage.

This is a developing story, more information will be added as it becomes available.

The Associated Press contributed to this report.