If the direct LAN fix fix continues to fail (e.g., you are in a dorm with strict network policies), use a virtual LAN:

mode; the VPN will treat the connection as a direct local link, often bypassing standard server lag. Troubleshooting Common Connection Issues

To understand the solution, you must understand the problem. When launched on PC in 2013, Capcom implemented an awkward hybrid system. The game nominally supports LAN play, but it routes connection discovery through Steam’s overlay and matchmaking servers , even for local networks.