Planes across the United States stopped flying Wednesday afternoon due to software issues. The FAA has already delayed or canceled more than 1,200 domestic flights, though the nature of the problems is unclear.

Written by the Federal Aviation Administration, the national regulator of air traffic In a short statement All domestic flights are temporarily not allowed to take off or land. This applies anyway until 3pm Dutch time, which is between 6 and 9am in North America. Some flights to and from the country have also been canceled or delayed.

Flights were delayed due to a malfunction in the air task system notice, or notam. it’s a System Flight crews and airline managers receive last-minute flight updates. This includes, for example, information about airports of departure or arrival, or about procedures and weather on the way. The FAA says this system is currently out of action across the country.

The FAA is currently trying to restart the system after it “failed”. The aviation authority does not provide details of what exactly went wrong with the system and what caused the delay. For example, the FAA doesn’t say whether it was a faulty update or a cyberattack, for example, though there is much speculation about the latter.