Whenever my brother and I start a new world on my laptop and open the LAN server we can play for a few days, but then my brother will suddenly not be able to even see the LAN server open. It recently happened on an unmodded 1.12.1 world, two days ago we could play and connect without any problems but now whenever I open to LAN he can't find the option to join and directly connecting doesn't work either. This has happened multiple times on different versions, modded and unmodded. It has never happened when my brother starts the LAN server, but his games are usually much laggier for both of us so I would prefer to keep using my laptop as the main server.
Whenever my brother and I start a new world on my laptop and open the LAN server we can play for a few days, but then my brother will suddenly not be able to even see the LAN server open. It recently happened on an unmodded 1.12.1 world, two days ago we could play and connect without any problems but now whenever I open to LAN he can't find the option to join and directly connecting doesn't work either. This has happened multiple times on different versions, modded and unmodded. It has never happened when my brother starts the LAN server, but his games are usually much laggier for both of us so I would prefer to keep using my laptop as the main server.
LAN connection issues are usually caused by overprotective antivirus/firewall.