Online sales specialist Ticketmaster was hit by a cyber-attack in November that it says led to the problems with ticket sales for Taylor Swift’s upcoming US tour.

Speaking to a congressional committee, the president of its parent company Live Nation said that a massive influx of traffic on the Ticketmaster website caused the slowdown in ticket sales.

Significantly, according to Joe Berchtold,  part of that was due to a cyberattack, Joe Berchtold, president of Ticketmaster parent company Live Nation, said.

During the Swift concert sales, Ticketmaster was “hit with three times the amount of bot traffic than we had ever experienced, and for the first time in 400 Verified Fan on-sales, they came after our Verified Fan access code servers,” Berchtold said.

The incident led Ticketmaster to become a target of approbation from Swift’s fans and legislators, who have been levelling accusations of antitrust violations and have called for curbs on the company’s supposed market dominance.

Berchtold emphasised in his remarks that the hackers did not manage to illegally obtain any tickets:

“While the bots failed to penetrate our systems or acquire any tickets, the attack required us to slow down and even pause our sales,” Berchtold he said. 

In his testimony Berchtold also described an “arms race” between companies such as Ticketmaster and cyber criminals looking to illegally obtain tickets for resale, and apologised to Swift and fans alike for the consumer experience.

According to reports, two people familiar with the cyberattack, granted anonymity to speak about the incident ahead of the hearing, said that a culprit for the attack — which took several hours for the company to address — has not yet been identified. 

They said Ticketmaster reported the attempted attack to the Federal Trade Commission and to the FBI, which are looking into the incident.

Separately, Ticketmaster denies the anti-competitive allegations.