Many supporters decided to queue at Valley Parade after their attempts to buy tickets online came to nothing.
Some queued more than five hours in freezing conditions on Saturday only to be told that all the tickets had gone.
Last night a club spokesman admitted that the online ticketing system had been unable to cope.
He said the system had “slowed up” due to “unprecedented demand” from fans across Britain and abroad.
“To all Bradford City fans who haven’t got tickets, we sympathise,” said the club spokesman.
“We appreciate that our ticketing system, to some extent, couldn’t cope with demand.”
He said almost 6,000 tickets had only arrived late on Friday which had placed added pressure on staff.
Season ticket holder Gary Thornton said: “It should have been fairly obvious that the issues with the online system would cause an influx of emails and that many more fans would turn up at the ground - it’s not rocket science.
“Accordingly, the club could and should have made sure that provisions were made so that fans were dealt with effectively and expediently rather than letting us stand for hours in the cold and snow.”
He said the club ought to have had more staff on duty.
Last night there was a little bit of positive news. The club said it would ask for more tickets, although it doesn’t expect to get any.