A school in Norway has stopped using popular video conferencing service Whereby after a naked man apparently “guessed” the link to a video lesson.

According to Norwegian state broadcaster NRK, the man exposed himself in front of several young children over the video call. The theory, according to the report, is that the man guessed the meeting ID and joined the video call.

One expert quoted in the story said some are “looking” for links.

Last year security researchers told TechCrunch that malicious users could access and listen in to Zoom and Webex video meetings by cycling through different permutations of meeting IDs in bulk. The researchers said the flaw worked because many meetings were not protected by a passcode.

School and workplaces across the world are embracing remote teaching as the number of those infected by the coronavirus strain, known as COVID-19, continues to climb. There are some 523,000 confirmed cases of COVID-19 across the world as of Thursday, according to data provided by Johns Hopkins University. Norway currently has over 3,300 confirmed cases.

More than 80% of the world’s population is said to be on some kind of lockdown to help limit the spread of the coronavirus in an effort to prevent the overrunning of health systems.

The ongoing global lockdown has forced companies to embrace their staff working from home, pushing Zoom to become the go-to video conferencing platform for not only remote workers but also for recreation, like book clubs and happy hours.

An earlier version of this article incorrectly identified the video service as Zoom. The video conferencing service used by the school was Whereby. We regret the error.