Southwest Airlines canceled hundreds of flights Monday on the heels of a snake-bitten weekend plagued by nearly 2,000 canceled flights reportedly due to weather and staffing issues.

Monday’s issues at the Dallas-based airline included a technological outage, according to Downdetector, which tracks problems related to company websites and check-ins.

“It’s never our intention to make travel more difficult,” the airline tweeted Monday morning. “Please know that we work hard to staff accordingly, and appreciate you hanging in there with us as we worked to get you going.”

Flight Aware reported that nearly 350 flights had been canceled as of 7 a.m. Monday, and that more than 300 other Southwest flights were facing delays.

Voices on social media were complaining of staffing shortages.

The 1,018 flights grounded by the airline on Sunday amounted to more than 25 percent of its scheduled flights, according to USA Today.

Hubs in Denver, Baltimore, Dallas Love Field, Las Vegas and Chicago Midway were said to be the hardest hit. Major delays were also seen at Atlanta’s Hartsfield-Jackson International Airport.

Southwest also canceled more than 800 flights on Saturday.

Last week, the airline announced that it would start requiring its employees to be vaccinated against COVID-19 in response to a mandate issued by President Joe Biden’s earlier this year.

The pilots union that serves the airline filed a lawsuit last Friday to stop the company from implementing the mandate.

At the same time, The Southwest Airlines Pilots Association gave the OK for its members to protest, claiming the vaccination order violated terms of the Railway Labor Act, which governs airline-union relations, according to a report by Newsweek.

But the pilots union later said that a strike wasn’t happening.

“SWAPA is aware of operational difficulties affecting Southwest Airlines today due to a number of issues, but we can say with confidence that our Pilots are not participating in any official or unofficial job actions,” the union said in a statement. “Our Pilots will continue to overcome SWA management’s poor planning, as well as any external operational challenges, and remain the most productive Pilots in the world. They will continue to be focused on their highest priority — safety. SWAPA Pilots are true professionals and will always maintain the highest level of responsibility to their crews, their passengers, and our airline.”

Over the weekend, the airline blamed the problems on weather and air traffic control issues.

“We experienced significant impact in the Florida airports (Friday) evening after an FAA-imposed air traffic management program was implemented due to weather and resulted in a large number of cancellations,” the airline said in a statement Saturday. “We are working hard behind the scenes to minimize challenges and fully recover the operation as we take care of displaced crews and customers as quickly as possible. We will continue to reset our network today and hope to return to close to normal operations as we move into Sunday.’’

But the FAA said its actions were not substantial enough to disrupt air traffic to that degree, according to the New York Daily News.

“No FAA air traffic staffing shortages have been reported since Friday,” the FAA said in a statement. “Flight delays and cancellations occurred for a few hours Friday afternoon due to widespread severe weather, military training, and limited staffing in one area of the Jacksonville Air Route Traffic Control Center.”

There were many — including stranded passengers — who were skeptical that the problem wasn’t directly related to the vaccine mandate.

This is a developing story. Please stay with AJC.com for the latest details.