Atlanta Public Schools’ all-virtual opening day Aug. 24 was partly interrupted by a massive outage in the teleconference service Zoom. DeKalb and Fulton counties’ school systems say the outage did not significantly affect them.

APS issued a social-media alert that morning that Zoom was down for many users. The service was back in time for Superintendent Lisa Herring to virtually visit students around noon, according to APS spokesperson Ian Smith.

In its own social media posts, California-based Zoom said it had fixed the issue within a couple of hours. “We know the responsibility we have to keep your meetings, classrooms & important events running,” said Zoom founder and CEO Eric Yuan on Twitter. “I’m personally very sorry & we will all do our best to prevent this from happening in the future.”

Smith said that APS teachers are using a variety of platforms, so the virtual reopening of school did not rely solely on Zoom.

The DeKalb and Fulton school systems, which started their school years virtually earlier this month, also do not rely on Zoom. Both systems said they primarily use Microsoft’s Teams platform.

Shumuriel Ratliff, a spokesperson for the Fulton County School System, said the “more secure connection” of Microsoft Teams is preferred by the district. “Other platforms, including Zoom, are not supported nor encouraged for virtual meetings,” Ratliff said.

All three school districts have reopened virtually due to the COVID-19 pandemic and have varying benchmarks for returning to in-person or hybrid learning.