In a statement issued on X, the carrier said it was “experiencing an IT outage that’s impacting our operations,” and has requested a “temporary, system-wide ground stop until the issue is resolved.”

The company’s statement didn’t offer an details about the nature of the IT outage or specify how long it expects the ground stop to remain in effect.

The airline urged its passengers traveling on Sunday night to “check the status of your flight before leaving for the airport.”

According to a Federal Aviation Administration advisory, the airline first requested a ground stop for only the Alaska Airlines fleet, but this was was later expanded to include Horizon Air flights as well.