UCAS apologised that its website was “running slowly” on Twitter but added that it should now be working as usual.
Students continued to report issues afterwards, with one person saying they had been trying to log in for 33 minutes without any success.
Pictures posted earlier on social media from frustrated students showed the UCAS Track page showing a message which read “a timeout occurred”.
Others said that their UCAS Track page was not updated after they were able to log in.
UCAS told the Evening Standard it saw a surge in demand for the website at 8am that was seven times higher than at the same point last year.
“We immediately responded and increased our capacity and the service returned to normal within thirty minutes,” said the UCAS spokesperson.
“We apologise for the frustration this has caused, and we are here to help students throughout the day.”
One student tagged UCAS Track in a tweet that simply said: “UCAS LET ME IN”.
The service issue came at a crucial time for students who were eager to find out their results.
“Stayed up all night just for ucas to not work,” said another student on Twitter as many shared memes that expressed their disappointment.
UCAS figures showed more students have been accepted on to UK degree courses this year.
In total, 358,860 people from across the UK have had places confirmed, up 2.9 per cent on the same point last year, according to data published by the university admissions service.
It comes as A-level students were warned to be patient with clearing staff, many of whom are working from home.
With the coronavirus pandemic keeping staff at many universities at home, students – who are expected to apply through clearing in record numbers – have been warned that getting a place could take longer than usual.
The figures show that 34,310 international students from outside the EU have been accepted (up 2 per cent), while acceptances from students within the EU have fallen by 15.2 per cent, to 22,430.
A total of 415,600 students have a confirmed place on an undergraduate course in the UK. This is a 1.6 per cent increase on results day last year.
The figures come on the day that students across England, Wales and Northern Ireland are receiving their A-level results.