RALEIGH (AP) — North Carolina’s public schools returned to class on Monday, with most students still learning from home through computers to start the year due to continued worries about COVID-19.

Nearly every school in all K-12 districts began the new school year. Leaders of districts and charter schools that teach two-thirds of the 1.5 million public school students chose to implement full-remote learning for now, according to data from the Department of Public Instruction.

The first day was marked by technical challenges beyond those that video conferencing and virtual learning bring. Districts reported trouble for children and instructors logging on to the North Carolina Education Cloud. The portal provides access to several digital applications, including tools for grading and attendance, instructional materials and lesson plans.

“The product experienced a degradation in service this morning,” the Department of Public Instruction said in a news release. The service was working as of midday Monday, the agency said, and the vendor that provides the service will expain what went wrong. In a Facebook post, the Craven County Public Schools said the system experienced an “overload due to so many students across the state trying to login at the same time.”

Under Gov. Roy Cooper’s plan, school boards could start the year by offering full remote learning, in-person instruction with strict social distancing or a mix.

School buildings were shuttered in March amid the pandemic and never reopened this past year.

School districts are expanding their online instruction. More than half of Wake County’s school enrollment signed up for the district’s “virtual academy.” However, the State Board of Education declined last week to increase enrollment for two virtual charter schools.