AER Lingus has cancelled all flights departing Dublin Airport for British and European destinations for the rest of the day.
A major technical problem has prevented passengers from checking in, causing huge delays and queues at the airport.
The airline is now cancelling its short-haul flights and telling those passengers not to come to the airport today.
A statement from Aer Lingus said: “Due to a major incident with a network provider, our cloud-based systems enabling check-in, boarding and our website are currently unavailable.
“A UK network provider servicing the cloud-based system has experienced a major break in connectivity impacting both primary and secondary connectivity. At this time the provider has not been able to give Aer Lingus an estimate of the time when the break in connectivity will be restored.
“Unfortunately, this is causing severe disruption to Aer Lingus services today. Consequently, all flights originally scheduled to depart from Dublin Airport for European and United Kingdom destinations from 2pm onwards today have had to be cancelled.
“As we are currently unable to communicate directly with customers, we are asking customers booked to travel on those flights not to come to Dublin Airport.
“We sincerely apologise to all customers impacted by today’s disruption and cancellations.
“Any customer impacted by today’s disruptions will be able to change their travel plans, free of charge either through our call centre or social media channels. We will advise customers when IT systems are restored and this change option is fully available to our customers.
“As soon as systems are restored our teams will work to re-accommodate those impacted as efficiently as possible, and share information regarding customers’ rights and the airlines’ obligations under Regulation (EC) 261/2004.
“We are working intensively with our system partners and their network partners to resolve the connection issues as soon as possible.”
Passengers had been facing long queues at Dublin Airport this morning due to the technical fault in Aer Lingus’ check-in system.
People waiting in terminal two have been venting their frustration online.
One twitter user wrote: “I got here around half seven, I just want to check in and not miss my connection in London.”
While another said: “For the past 2h. We are just here sitting on the floor while people tell us that they are working on the fix.”
Just before 11.30am, Dublin Airport said on Twitter: “Due to an IT outage AerLingus is experiencing an internal issue at present impacting their check in and boarding processes.
“As they work to resolve the issue we ask Guests to cooperate with our teams. This is not impacting any other airlines. We thank everyone for their patience.”