The most common cause of LAN connectivity failure is the Windows Firewall blocking game traffic. Both host and client computers must allow the game through the firewall. Add Firewall Exceptions Open the , type firewall.cpl , and press Enter .
If both PCs use the same steam_api.dll without regenerating a unique user_id , the game thinks you are the same player and hangs on a black loading screen.
If the V4 crack alone doesn't immediately show your friend's lobby, you are likely facing modern OS interference (Windows 11 updates) or router issues. Follow this layer-by-layer checklist.