"Widespread technical issues" cancelled the Ontario Secondary School Literacy Test (OSSLT) Thursday, the first time the test was being offered online in a "field readiness" evaluation of the new system.

The glitch prevented Grade 10 students from logging into the test at its scheduled 9 a.m. start time.

According to a notice posted to the website of the Education Quality and Accountability Office, the glitch caused a system lag.

A follow-up message urged students to reboot the system at 10 a.m. But that apparently did not solve the problem.

"We acknowledge that we are experiencing widespread technical issues with the online OSSLT network," read a statement posted to EQAO's website shortly before 11:30 a.m. "We regret to inform you that we have cancelled today's assessment."

Some schools gave up and cancelled the test before the EQAO's announcement, wanting to salvage at least a few hours of class time for the students.

ATTN: Due to technical issues being experienced across the province with EQAO testing, UGDSB will not be conducting the OSSLT today —@ugdsb

The OSSLT was cancelled today due to issues at EQAO. Classes will resume as normal commencing period two. —@principal_edhs

Earlier Richard Jones, director of assessment at the EQAO, said he "wasn't 100 per cent confident" that the reboot would work. Thursday's test was supposed to be a tryout of the "field readiness" of the online system, he said.

"All of the work we've done testing the system up to today was very, very satisfactory," Jones told CBC News. "I thought we were in a very good position to conduct the test."

He couldn't immediately explain why the glitch happened. In a follow-up interview, Jones said that at first, administrators thought there was a problem with the Internet lines connected to the host servers. But when the re-boot failed to fix the issue, it became clear that "something else was going on."

"We were certainly not in a position where we were going to keep students sitting in classrooms waiting to do an assessment when we didn't even have the answers to what the issue was, let alone correcting it," Jones said.

The EQAO and the vendor contracted to run the online system are working to determine exactly what happened, he said.

Ontario Education Minister Mitzie Hunter said she is confident that the problem can be fixed before the next set of tests, scheduled for spring.

"It's important for students to have the option to write the test online," Hunter said. "It's unfortunate that the technology did not support that today. EQAO has committed to doing a full investigation of what occurred and they will make that available publicly."

Before the test was cancelled, and with some extra time on their hands, students took to social media to complain.

<a href="https://twitter.com/hashtag/OSSLT?src=hash">#OSSLT</a> I JUST SAT IN THE LIBARY FOR AN HOUR DOING NOTHING. NOTHING!! —@joelleannak

1 hour into <a href="https://twitter.com/hashtag/OSSLT?src=hash">#OSSLT</a> and chill and I've taken 3 naps and played 4 rounds of 7-up —@hollythomsn

the teachers when u ask them why the server keeps logging u out <a href="https://twitter.com/hashtag/OSSLT?src=hash">#OSSLT</a> <a href="https://t.co/u3cZbJW7Ix">pic.twitter.com/u3cZbJW7Ix</a> —@alyssapereiraa

Did they really think doing this online would be a good idea when every grade 10 student in ontario would be on the same site... <a href="https://twitter.com/hashtag/OSSLT?src=hash">#OSSLT</a> —@nochillmartina

"How long will student's patience last? Use evidence from the text to support your answer. <a href="https://twitter.com/hashtag/EQAO?src=hash">#EQAO</a> <a href="https://twitter.com/hashtag/OSSLT?src=hash">#OSSLT</a> —@GeraldtonSteve

'Really, really disappointing'

The glitch does not mean that all Ontario students were left unable to write the test. Individual schools chose whether to participate in the online version.

According to Jones, 800 of the province's 900 secondary schools were registered. While he couldn't say how many students would have taken the test, his best estimate was between 100,000 and 130,000.

Asked whether the problem may have been simply a matter of too many people trying to log in at once, he said previous testing was based on a load capacity far greater than the system would ever have to accommodate.

He called Thursday's outcome "really, really disappointing," particularly given the work that boards, schools and students put into preparing for the test.

"We obviously didn't expect that we'd have to bring the whole testing system down today," he said.

Thursday's online test was a voluntary trial, and the regularly scheduled OSSLT tests will go ahead in March as planned. Those tests are supposed to be online, with all registered students also having a back-up paper copy, Jones said.

The EQAO anticipated technical difficulties. It included detailed instructions on its website for school administrators to follow in case of a glitch