A severed fiber cable line that delivers internet across the state caused yet another halt to TNReady testing on Thursday.

"The telecommunications industry has confirmed the main fiber cable between Nashville and Atlanta has been cut," the state Department of Education said in an email to district leaders Thursday morning. "Telecommunication vendors are reaching out and calling impacted districts directly, and we will continue to keep you posted as we learn more from them."

Some districts, including Knox County schools, said they would suspend testing for the day.

"Due to technical difficulties with the state online assessment platform, several schools have been unable to submit their students’ responses today. The district has decided to suspend testing this morning until these issues are resolved," Knox County School Spokesperson Carly Harrington said.

Anderson County also said it would cancel testing Thursday.

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A Metro Nashville Public Schools spokesperson said it was a school-level decision whether to try to continue with testing. Some schools had cancelled for the day.

The state said internet traffic is being routed to back-up channels, there could still be slowdowns.

"This is an issue related to local connectivity, not with the testing platform," the state said. "Testing can continue, but connectivity may be slow in areas that are impacted until this is resolved."

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The internet issues are at least the fourth issue with TNReady online testing since exams began April 16. The first day, students could not log into the system. The second day, an apparent cyber attack, now under investigation by state agencies, caused a full system shutdown.

This week, the testing vendor, Questar Assessments, completed a software update overnight that caused online rosters that had been customized for some schools to be reset to a default list.

Last week, the legislature took action to make sure students and teachers aren't penalized for poor results on this year's tests. Test results this school year will count only if it benefits students, educators and districts.

Districts can’t base employment or compensation decisions based on the data, the legislation says.

Reach Jennifer Pignolet at jennifer.pignolet@commercialappeal.com or on Twitter @JenPignolet.