Reply To: Possible Bug on Big Sur
OK, so it’s not the browser (unless it is rather old and not updated).
Why are you sure that the port forwarding works?
The only thing where you can see that it works is the three digit code in parentheses after the UDP2 value when pointing on your own or your partners name. Please check and post the numbers of you and your student here.
Please note that if you have WLAN enabled and a LAN cable connected, the preselected IP-address at the stage is always the smallest. If this is the WLAN-address, the port forwarding might be correctly set at the router, but usually for the LAN-IP-address which is not used then. In that case the three digit number will show that the port forwarding does not work (middle digit is 8 then).
A second reason why it might not work is when the computer’s IP-address is not fixed to the port forwarding IP-address.
The fixing could be done at the router (binding the IP-address to the computer’s network interface MAC-address, which is usually represented by the computer name as given to the operating system) or by using a static IP-address (usually leads to problems in other networks, so use only on LAN-interface and be sure this number is outside the DHCP address range (which is usually defined at your router). DHCP usually gives a new IP-address after a while of not using the interface (happens mostly on the less used LAN-interface), so it might work in the beginning but not later. But the three digit number tell you if it works or not.
If it is a two participants communication only, only one needs to have full connectivity with a port forwarding. So one of you (preferably you as you are the teacher and it only needs to be done once), should have a 1 or 2 as the second digit. If not, you should check your port forwarding and correct it. In that case all students regardless of any port forwarding on their side should be able to connect to you. So, what is your 3-digit number?
You might also try to check what happens if you accept all incoming connections (for a short while during the student connecting). Does a connection get established then? If it works then, you can go back to the asking for a connection attempt setting.