Minnesota put an abrupt halt to mandatory online proficiency testing Tuesday after repeated glitches frustrated students and teachers for a third day.

Brenda Cassellius, state education commissioner, said in a statement late Tuesday that all testing would be suspended until provider Pearson could fix the system. Pearson is an international firm that is one of the nation’s largest providers of academic assessments.

“Students already give up precious instructional time for annual accountability tests,” Cassellius’ statement said. “We cannot allow these disruptions to further impact student learning.”

For the third time since April 14 students across the state were unable to log in or had testing slow to a crawl Tuesday morning. Districts around the Twin Cities area and across the state reported problems about 8:30 a.m. Tuesday.

The system was working normally by 11:15 a.m., but the morning problems forced some schools to delay or reschedule student tests. In Farmington, for example, many students were unable to log in to the testing system, and those who were already taking assessments experienced a slowdown.

“We did have a couple of buildings manage to continue testing at a frustrating slow pace, but most canceled their morning session,” said Farmington Superintendent Jay Haugen.

The difficulties are like those experienced by students, teachers and administrators for part of each day April 14 and 15. Similar issues appear to have affected test-taking in other states that contract with Pearson for online proficiency tests.

Cassellius said she told Pearson representatives that Minnesota students would not resume testing until the system is “error-free.”

“We hold our students to high standards and we expect no less of Pearson. Students deserve a worry-free testing experience without interruptions,” Cassellius said.

A Pearson representative did not immediately respond to a request for comment.

Minnesota has a $38 million contract with Pearson to provide the Minnesota Comprehensive Assessments, or MCAs, in reading, math and science. Federal law requires students take proficiency tests in third through eighth grades and once in high school, and a 2013 Minnesota bill required the tests be online by this spring.

Two Pearson systems are at the heart of Minnesota’s online test administration. Teachers and administrators use Pearson Access to manage student test-taking, and students use TestNav to take assessments.

A Pearson website that updates school officials on the status of those two systems said Tuesday morning that both were operating in a “degraded way” in Minnesota and other states. Arizona, Colorado, Florida, Maryland, Mississippi, Oklahoma, Tennessee, Texas and Virginia use online testing systems from Pearson similar to what Minnesota uses.

“Primary symptoms of this condition include user difficulty logging in, slow test item download, slow test submissions and a warning screen to notify their teacher or test proctor,” the website said. “While such conditions are frustrating, online testing may continue at this time.”

It is unclear how many Minnesota students were affected by the problems.

Minnesota Department of Education officials said that between 17,000 and 19,000 students were taking tests online Tuesday. About 400,000 tests have been completed without problems since the MCA testing window opened in March, officials said.

Educators worry unreliable online tests will frustrate students and drive down their performance.

On April 14, a server crash caused a similar problem with the Pearson Access system used to manage test administration. Some schools also experienced slowness with the system last on April 15.

State education officials have said the issues with Pearson’s system are not as bad as 2013, when a computer crash derailed tests across the state and the MCA testing window had to be extended.

The 2013 crash happened when Minnesota used the American Institutes for Research, or AIR, as an online testing vendor. Problems with those online tests contributed to AIR and Minnesota no longer working together.

Christopher Magan can be reached at 651-228-5557. Follow him at twitter.com/chris_magan.