Thousands of people tried to log onto the ticket website when it opened at 9 a.m. local time Saturday, causing the website to slow, the BBC reported. Many people missed out on purchasing tickets "due to the sheer volume of people" on the website, the festival's official Twitter feed said.
Festival organizer Emily Eavis tweeted, "Sorry to everyone who missed out and for any problems you had with the booking site."
Tickets to the June 2013 festival held at Worthy Farm in Somerset cost $330, up $16 from last year's event. Any returned tickets will be made available for purchase in April, the BBC reported.
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