(CNN) – Delta Air Lines dealt with a brief computer system outage Tuesday evening.
Passengers were complaining on Delta’s Twitter page, saying they could not sign in or access their boarding pass on the app.
The airline grounded flights during the outage.
Around 8:30 p.m. ET, Delta told those passengers the issue was with the airline's computer system, but did not elaborate, saying only that technical support was working to fix the issue.
About an hour later, the airline tweeted that "Delta teams have restored all IT systems after a technology issue briefly affected some of our systems this evening. All groundstops have been lifted."
.@Delta teams have restored all IT systems after a technology issue briefly affected some of our systems this evening. All groundstops have been lifted.
— Delta News Hub (@DeltaNewsHub) September 26, 2018
It's unclear how many people or flights were affected by the problem, but Delta said flights already in the air during the outage weren't affected.
Copyright 2018 CNN. Raycom News Network contributed to this report. All rights reserved.