You can't use a Virtual Private Network (VPN) with the SYNKii Classroom.

A VPN will interfere with your connection, as SYNKii uses peer-to-peer technology to establish a video call. 

If you have already opened the classroom with a VPN enabled, disable your VPN and refresh the page.

For more information on VPNs, check out the NordVPN website: https://nordvpn.com/what-is-a-vpn/