The GAA is promising to investigate why some people hoping to buy tickets to this weekend's semi-final lost their place in the online queue.
Thousands of fans missed out on securing tickets to Saturday's clash between Dublin and Mayo, after spending hours in a virtual queue.
Many fans who lined up outside 370 Supervalu and Centra stores also missed out, but more tickets are on sale today.
Spokesperson for the GAA, Alan Milton, said it was an extremely busy and demanding day.
"The system didn't crash. That was communicated by tickets.ie at noon yesterday," said Mr Milton.
"We will be looking into some complaints that people lost their place in the queues.
"The reason why there is a queue system is that people can get onto the system and they're not just met with a brick wall when they try and purchase tickets.
"The sheer demand was probably the greatest demand we have had for a semi-final since Dublin played Mayo back in 2015."
Dublin and Mayo have met in the later stages of the All-Ireland football championship many times over the last few years.
The sides squared off in the final in 2013, 2016 and 2017 and in the semi-final in 2015.
The sides will meet again at GAA HQ on August 10 in the first of this year's semi-finals.
The winners will take on either Kerry or Tyrone in the final on September 1.