A computer security breach is not to blame for Sunday's service disruptions at Southwest Airlines, the company claims. The technical glitch caused over 800 delays and numerous late bags, but there is "absolutely no evidence" the software failure that caused the problems was due to any cyber break-in, according to spokesman Brad Hawkins.

Just 75 percent of scheduled flights on Sunday arrived at their destinations. The company was working to get bags delivered and passengers moving by using backup procedures, and normal system service was expected to resume Monday.

Angry passengers took to Twitter to complain about what was perceived as poor handling of the situation.

Southwest is working to answer customer questions and concerns on Twitter. The company has also given customers scheduled to fly Sunday or Monday the option to change their plans on the airline website.

The incident is not the first time this year Southwest has been hit by computer complications. The airline was one of several hit by an air traffic control center predicament in August. The incident led to over 440 flights from numerous airlines being grounded throughout the U.S. East Coast. The Federal Aviation Administration stated the issue was due to a problem with a flight-tracking system.