World War Z: Aftermath cover

World War Z: Aftermath multiplayer not working? Fix it here.

Co-op zombie shooter on PC, PS, Xbox & Switch (full crossplay).

SteamPSXboxSwitch4 playersCrossplay ✓
Co-op type
online
Invite method
Platform friends or lobby code
NAT needed
Moderate or Open
Ports
Steam P2P: UDP 27015–27030

Crossplay: Full crossplay across PC (Steam/Epic), PlayStation and Xbox.

What's happening? Pick your symptom

All World War Z: Aftermath co-op fix guides

Can't join friends in World War Z: Aftermath

On Steam / PS / Xbox / Switch, friends join via the platform friends list or a lobby/join code — use the code if invites fail.

  1. Use the lobby / join code instead of a friend invite — Steam and platform friend-invites fail far more often than copy-paste codes. Most co-op games have a 'share lobby code' button.
    • Host creates the lobby, then copies the lobby/join code (not the friend invite).
    • Send the code in chat; the joiner pastes it into 'Join with code'.
    • If invites still fail, this bypasses the broken invite pipeline entirely.
  2. Check and fix your NAT type — Strict NAT is the #1 cause of 'can't join friends'. You need Moderate or Open to host and to receive invites reliably.
    • On Steam: Settings → In-Game → check the 'NAT' indicator, or test via Steam's network settings.
    • On Xbox: Settings → General → Network settings → 'NAT type'.
    • On PlayStation: Settings → Network → View Connection Status → 'NAT Type'.
    • If Strict: enable UPnP and/or port-forward (see those fixes). Tether to a phone hotspot once to confirm — if it works there, the issue is your home router.
  3. Restart Steam / Epic / the console client — The overlay and friend-presence service occasionally desyncs, so invites never arrive. A client restart re-syncs it.
    • Fully quit Steam/Epic (system tray → Exit, don't just close the window).
    • Reopen and log back in.
    • On console, quit to dashboard and restart the app.
  4. Host creates the lobby, then friends click 'Join' in the friends list or paste the lobby code.
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World War Z: Aftermath multiplayer not working

  1. Power-cycle your router and relaunch the game — A 30-second router reboot clears stale NAT and UPnP leases that silently break peer-to-peer connections. Fully quit the game (don't just minimise) and reopen it.
    • Unplug the router for 30 seconds, then plug it back in and wait for full sync.
    • Completely close the game (check Task Manager / Force Quit — overlays can leave it running).
    • Relaunch the game and try joining again.
  2. Enable UPnP on your router — UPnP lets the game open its own port automatically. With it off, you'll often get Strict NAT and can't host or receive invites.
    • Log in to your router admin page (usually 192.168.0.1 or 192.168.1.1).
    • Find 'UPnP' or 'Universal Plug and Play' and turn it ON.
    • Save and reboot the router, then retry the game.
  3. Turn off VPN, proxy, and 'kill switch' tools — VPNs and routing tools reroute P2P traffic and trigger Strict NAT or total blocks. Disable them for the session.
    • Fully quit your VPN app (not just disconnect — quit it).
    • Disable any proxy in Windows Settings → Network → Proxy.
    • Temporarily uninstall 'kill switch' / firewall-overlay tools if the issue persists.
    • Retry the join with a direct connection.
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World War Z: Aftermath connection failed / dropped

  1. Allow the game through firewall & antivirus — Over-aggressive security software flags game executables as threats and drops the connection after join.
    • Windows: Allow the game .exe through Windows Defender Firewall (Private + Public).
    • Add the game and Steam/Epic to your antivirus allow-list.
    • On Mac: System Settings → Privacy & Security → Firewall → allow the game.
  2. Verify game files (fixes corrupted installs) — A half-downloaded or corrupted file causes 'connection failed' right after joining. Verifying redownloads the broken bits.
    • Steam: Library → right-click game → Properties → Installed Files → 'Verify integrity of game files'.
    • Epic: Library → three dots → 'Manage' → 'Verify'.
    • Console: a corrupted install usually needs a full reinstall from the store.
  3. Use a wired connection to stop lag & drops — Wi-Fi jitter causes 'connection failed' and mid-session drops. A cable removes most of it.
    • Plug in Ethernet instead of Wi-Fi for the host especially.
    • If Wi-Fi only, move close to the router and use 5 GHz.
    • Close bandwidth-heavy apps (streaming, downloads) during play.
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World War Z: Aftermath crossplay not working

Full crossplay across PC (Steam/Epic), PlayStation and Xbox.

  1. Enable the in-game crossplay toggle — Crossplay is OFF by default in many games. Both players must turn it on, or a Steam player simply can't see an Xbox/PS player.
    • Open the game's multiplayer / network settings.
    • Turn ON 'Crossplay' (or 'Cross-platform play') on every player's client.
    • Restart the lobby after changing it — the setting often only applies to new sessions.
    • If your platform combo isn't supported, see the crossplay note on the game's page.
  2. Make sure everyone is on the same version & region — Even a one-patch difference blocks joins. Test branches, beta opt-ins, and region settings must all match.
    • Confirm all players are on the same game version (no one on a beta/test branch).
    • Match region/server selection in the game's settings.
    • If one player is on Steam and another on a different store, check the crossplay note on the game's page.
  3. Match server region — If players pick different data-center regions, the lobby won't appear to each other. Align regions before inviting.
    • Each player opens the game's server/region picker.
    • Select the SAME region (closest to the majority).
    • Recreate the lobby after changing region.
  4. Make sure BOTH sides have crossplay enabled in the game's own settings and are signed in to the platform account the game expects (e.g. Xbox Live / PSN / Epic).
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World War Z: Aftermath error codes explained

FAILED TO CONNECT
Host NAT Strict. Host enables UPnP or shares the lobby code.
CAN'T JOIN
Crossplay must be ON; PC, PS and Xbox share one pool.