The website of the Central Applications Office is now active again.
It had previously crashed following a "malicious attack from an unknown source".
It comes as thousands of students across the country await college offers, the first round of which are being released today.
"The CAO is pleased to announce that our technical team has found a solution to issues caused by this morning’s attack on the CAO website," said Joseph O’Grady, CAO operations manager.
"We will continue to monitor the website closely with the aim of ensuring the continuity of our online services for applicants
"By 2pm today, over 15,000 acceptances were recorded, a similar level to the same time last year. If you accepted an offer today, you can log in to the ’My Application’ section of the CAO website over the coming days to confirm your acceptance has been recorded.
"Acceptances can be also be made by post.
"There is plenty of time for applicants to accept their offer, the deadline for acceptances is Monday August 30 at 5.15pm.
"Parents and students should note that offers should be accepted either online or by post, not both."