Commonwealth Games organisers have reported "unprecedented demand" for tickets as a further 100,000 went on sale to the public.
Glasgow 2014 chiefs apologised for delays and difficulties as sports fans attempted to snap up the latest release of tickets which include all 17 sports and the opening and closing ceremonies.
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A spokesman said: "Today's general ticket sale has generated unprecedented demand and with this the call centre and website is understandably very busy and there are queues in place to manage this.
"We would like to assure customers that we are processing ticket sales as quickly as we can and advise customers to keep trying. We thank everyone for their patience and apologise to those who have experienced issues."
Organisers said they had received reports from some customers of errors in the ticket selection and purchase process.
Sports fans who previously missed out on tickets and any last-minute buyers were given a chance to secure seats for this summer's event from 10am today on a first come, first served basis.
The 100,000 extra tickets became available as the final arrangements for venue layouts and spectator seating are made, Games chiefs said.
About 2.3 million applications were made for the initial one million tickets released last year, with athletics, aquatics and cycling proving the hottest tickets.
Glasgow 2014 chief executive David Grevemberg said: "We are delighted that it means even more people will get the opportunity to be part of the Games and experience live world-class sporting action here in Glasgow and Scotland.
"It is fantastic that the extra tickets are for all 17 sports and the ceremonies too. We know from experience just how high the demand will be for these tickets so while we are urging everyone to get in early and take the opportunity to join us at the Games this summer, we also need to thank them in advance for their patience and continued support.
"We have always said we wanted to make Glasgow 2014 Commonwealth Games accessible, affordable and available to as many people as possible and we very much look forward to welcoming the world to Glasgow and Scotland, for what promises to be an outstanding festival of sport."