If you are using LSL to synchronize data coming from multiple devices - laptops or mobile phones - you need to ensure the LAN network setup is correct. Please check all the steps below for a successful setup!
1. Make sure all devices are on the same Wi-Fi network, no need for a network with Internet access.
2. You need to use a dedicated router with a private network for the LSL communication to work properly.
3. Turn OFF firewall for all networks on your laptops. Go to your laptops Firewall settings and turn it off for all. Note: This is why it's important to use a dedicated router without Internet access. You will ensure your data is safe and not public.
4. Use the 5GHz Wi-Fi network, in case you have a lot of LSL streams.
5. Make sure your current network is configured as private on all laptops. You can do this by going to:
Network & Internet settings on your laptops. There, go to the Wi-Fi network you are connected to currently i.e. its settings. Or if you are connecting your devices via Ethernet cables, go to Ethernet network settings.
Here, make sure the network is configured as "Private" not public.