MIAMI — Due to an apparent computer outage, Southwest Airlines is experiencing flight disruptions late Wednesday afternoon.

Southwest acknowledged the computer glitch and are investigating the current issues. The Dallas-based carrier promised to update travelers on Twitter.

“Southwest Airlines began experiencing intermittent performance issues earlier this afternoon with multiple technology systems as a result of an outage. We [Southwest] 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 [Southwest] apologize to our Customers whose travel plans are impacted,” the airline said in a statement.

The statement also assures that Southwest has “A team of experts working diligently to resolve the technical issues and their efforts have systems gradually coming back online. We [Southwest] expect to continue our move toward a normal operation but believe it will take time.”

The airline’s website has also been affected by the outage, limiting its functionality to check-in and flight status only. The site shows an error page with the following message:

We’re working hard to get you where you want to be. Please do not refresh your browser. We will automatically transfer you to as soon as possible. Thank you for your patience.

Southwest Chief Communication Officer Linda Rutherford said I a tweeted video, “We know we’ve disappointed customers (…) and we’re really, really sorry about that. It’s unacceptable to us. (…) We know there are long lines at the airport and we really appreciate everyone’s patience.”

The carrier reduced the number of flights departing after 22:00 ET Wednesday, in an effort to fully restore its system for Thursday’s operations. “Flexible rebooking accommodation will be available to Customers once our systems are fully functional.” Southwest said in a statement.

At 09:30 ET on Thursday, July 21, 2016, Southwest reports that most of its systems are back online as of the start of its operational day. By 09:15 ET, the carrier had cancelled over 300 flights to manage lingering flight disruptions across the system.

The airline prompted customers traveling on Thursday to check the flight status on, and plan to arrive to the airport early, as long lines may occur.

Last October, an outage caused delays to approximately 800 Southwest flights, forcing employees to issue tickets and boarding passes by hand. At that time, the airline attributed the glitch to a software application, and the situation was solved in about a day.