Concert ticketing service Ticketfly says it's working to get its system back online after a data breach leaked users' personal information and disrupted services at live music venues.
The San Francisco firm's parent company, Eventbrite, said Sunday it's working with outside experts to investigate the hack.
It hasn't disclosed the details to customers, but a website that tracks data breaches says the leak affected more than 26 million user accounts.
The "Have I Been Pwned?" (POHNED) website also said Sunday that stolen data included email addresses, names, phone numbers and physical addresses.
The breach left nightclubs and other venues from Santa Cruz, California, to Providence, Rhode Island, scrambling for alternatives to sell tickets for weekend shows.
Eventbrite bought rival Ticketfly for $200 million last year from music service Pandora.