Delta was hit by a crippling computer outage on Sunday night that disrupted flights around the nation.
It’s the second time in less than six months that the U.S. carrier has suffered a major IT problem resulting in delays and angry passengers.
The FAA said late Sunday that there was a nationwide ground stop on all Delta domestic flights but that international flights weren’t affected.
“Delta teams are expeditiously working to fix a systems outage that has resulted in departure delays for flights on the ground,” the company said in a statement. “Flights in the air remain unaffected.”
Upset travelers took to Twitter to vent about the outages.
“@Delta I’m here in Atlanta will they let us know when things start working again?” wrote Twitter user @Indydog63.
The airline said it “apologizes to customers for the inconvenience.”
Delta’s website and mobile apps were also down, which added to customers’ frustrations.
The problems come about a week after United Airlines temporarily grounded domestic mainline flights due to an IT issue.
A previous Delta outage caused travel chaos around the globe.
In August, the airline lost power at its operations center in Atlanta setting off a system failure that resulted in around 2,000 flight cancellations over several days.
After that fiasco, Delta agreed to give affected customers refunds and vouchers for future travel.
— Tony Marco and Chris Isidore contributed to this article.