Mid-way through an online exam, thousands of Massey University students were locked out of the university's platform.
The networking fault impacted dozens of students whose exams had already been reshuffled because of the Covid-19 crisis.
An accounting student told the Herald she found only a black screen when she went to study for an upcoming exam.
"It's already stressful enough with all of the changes because of Covid," she said.
"I'm more annoyed than stressed ... It's the first day of online exams, so it doesn't bode well."
The second-year student had friends sitting online exams who were locked out of the platform.
"A lot of the exams have been moved to the evening, from 5pm til 8pm, because of the coronavirus," she said.
"I'm just trying to study, it would be unacceptable if you were in the middle of an exam."
Another student contacted a helpline and was told the issue should be resolved within half an hour, but was still locked out of her exam.
A Massey spokeswoman said a networking fault occurred between 6.55pm and 8.15pm, which impacted the learning management system (Stream) and the website.
"Any students sitting exams during the outage will not be disadvantaged," she said.
"Students will be granted extra time in their exam to compensate the time loss and they will be allowed a second attempt to complete their exam, with all their previous answers carried over."
The service should now be back up and running as usual, she said.
Massey University was among the many that moved to online learning as the Covid-19 pandemic worsened.
Classes were moved online, where possible, in late March in an attempt to reduce the spread of the virus.
Students were told pre-lockdown to prepare to study from home for an "extended period" as the university followed guidelines to limit the spread of Covid-19.
"Adhere to social distancing measures and hygiene practices at studio and lab classes that will continue to be taught face-to-face."
In-person teaching of courses, block courses and contact courses were to be halted temporarily as long as it didn't affect the quality of teaching.
New Zealand's biggest university, the University of Auckland, later announced it would run all courses remotely until Semester 2 starts in July - regardless of the Covid-19 alert level - fearing moving in and out of different alert levels will be too disruptive.
At alert levels 2 and 1, campuses would reopen for all activities (but no earlier than beginning of Semester 2) but with physical distancing and other precautionary measures.
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