DALLAS — Southwest Airlines said it was working Tuesday to restore normal operations after a technology-related issue interfered with flights for the second straight day.

By midafternoon, the nation’s fourth-largest airline had canceled about 500 flights and delayed nearly 1,300 others, according to tracking service FlightAware. The combination of cancellations and delays affected about half of Southwest’s planned flights for the day.

Spokesman for Dallas-based Southwest said a problem with connectivity of the airline’s technology systems started around midday Tuesday.

“Southwest is in the process of resuming normal operations after a brief pause in our flight activity resulting from intermittent performance issues with our network connectivity Tuesday afternoon,” the spokesman, Dan Landson, said in an email.

He said crews were working to limit flight disruptions, and urged customers to check their flight status Southwest’s website or seek help from the airline’s airport agents.

On Monday night, Southwest briefly grounded flights around the nation after problems with its third-party weather data provider.