In normal years universities match students whose A-levels were worse or better than expected with unfilled places on courses, with admissions staff working alongside student volunteers to manage the fast-paced process.
But 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.
Professor Richard Harvey, admissions tutor at the University of East Anglia, told the Times: “Most universities have installed expensive softphone solutions to route the usual influx of calls to staff working from home.”
“These systems are largely unproven and there are some horror stories of overhyped technology that cannot deliver on its promises.
“If your university isn’t picking up the phone then try them on live chat, assuming they have a live chat service, or email. There are plenty of places on offer so a couple of hours’ delay is not the end of the universe.”
UCAS, which acts as a go-between for students and universities, said that it expects record numbers of people to apply through clearing this year.
Up to 80,000 students could get places through clearing in 2020, about 7,000 more than last year, UCAS has predicted. Top universities still have more than 4,500 places unfilled.
And with foreign student numbers possibly set to fall amid a time of general uncertainty for universities, institutions may be competing to fill spaces through clearing, in what could be a "good year" for the UK's prospective students, UCAS' head said.
Clare Marchant added: "I think we will end up with significant numbers through clearing. I think it’s going to be probably the busiest yet.”
UCAS has added a new feature to its clearing service this year, promising to match students personally with courses that could be right for them.
But students may not need to go through clearing if they miss their grades. The government has urged universities to be "flexible" with A-level results this year, after exams were cancelled because of coronavirus.
It comes as education secretary Gavin Williamson admitted that students will not find out on Thursday if they are able to appeal their A-level grades .
The Government announced late on Tuesday that students in England will have the “safety net” of being able to use mock exam results as the basis for an appeal if they are higher than the calculated grade.
However, Ofqual's appeals process will not be ready in time for results today.