DENVER -- Southwest Airlines experienced a computer issue that delayed thousands of passenger at Denver International Airport and nationwide for several hours Wednesday afternoon.
DIA reported the problem was resolved and operations at Southwest returned to normal by early Wednesday evening.
But several hours later frustrated passengers were still have trouble getting on flights. The airport sent a message about cancellations and delays Wednesday night.
Due to technical issues earlier today, Southwest Airlines is experiencing delays and cancellations tonight. Please check your flight status
— Denver Int'l Airport (@DENAirport) July 21, 2016
The airline tweeted just before 1 p.m. MDT that it was aware and investigating the current issues. Southwest promised to update travelers on Twitter when it has updates.
RELATED: Check flight status at DIA
The airline's airport kiosks and website were not available for check-in or booking.
If you are seeing this image on the site you are in our waiting room. Don't refresh; we are working hard on a fix. pic.twitter.com/B1IDrDR2aC
— Southwest Airlines (@SouthwestAir) July 20, 2016
Some passengers reported that Southwest was issuing handwritten paper tickets to get fliers back in the air.
Southwest Airlines is the No. 4 U.S. airline by passenger traffic.
— Leesa Dillon (@Leesa_Dillon1) July 20, 2016
— Bun jamin (@Pizza_slaughter) July 20, 2016
— Jennifer S Daniel (@JeniferSDaniel2) July 20, 2016
The airline issued a statement Wednesday afternoon
“Southwest Airlines began experiencing intermittent performance issues earlier this afternoon with multiple technology systems as a result of an outage. We are now managing flight delays across our system, with a temporary ground stop in place for those flights that have not left the gate. We apologize to our Customers whose travel plans are impacted. We have a Team of experts working diligently to resolve the technical issues and their efforts have systems gradually coming back online. We expect to continue our move toward a normal operation but believe it will take time."