🎮 Game Error Codes What it means & how to fix it

Deep Rock Galactic Won't Let You Join? Here's the Fix

When Deep Rock Galactic hangs on 'Joining session' or kicks you with 'Connection to host has been lost', it's almost always NAT/UPnP blocking the peer connection, a version mismatch after an update, or a stale EAC service. Fastest fix in 2026: make sure both players are on the exact same build, enable UPnP on the host's router (or set NAT to Open), then rejoin from the friends list rather than matchmaking.

Deep Rock Galactic — why 'can't join session' happens

Crossplay boundary
Steam players are ISOLATED. Crossplay only works Xbox <-> Microsoft Store (Game Pass). Steam and MS Store cannot join each other (Steamworks vs Xbox Live)
Most reliable join
Use ESC -> INVITE FRIENDS in-game, not the Steam friends list
Branch check
Both players must be on the 'main' branch, not experimental, and lobby set to Public (ESC, bottom-left)
Quick fix
The joining player restarts the game; deactivating the firewall resolves it for many

Last verified: September 2026

Error codes

Stuck on 'Joining session' The join handshake started but the peer-to-peer connection to the host never completed.

Cause: Strict NAT / UPnP disabled on one side, or a firewall is blocking the game's UDP ports.

Fix:
  1. Have the HOST enable UPnP in their router settings, then both players restart the game.
  2. Allow DeepRockGalactic through Windows Defender Firewall (Private and Public).
  3. Both players verify the same platform build — a mid-season patch mismatch blocks joins.
  4. Join from the Steam/Xbox friends list -> 'Join Game' instead of public matchmaking.
'Connection to host has been lost' The session was established but the P2P link dropped mid-load or mid-mission.

Cause: Unstable NAT traversal, host's upload saturated, or an EAC re-init on one client.

Fix:
  1. Host should switch to a wired (Ethernet) connection to stabilise upload.
  2. Repair EasyAntiCheat: Steam > DRG > Manage > Browse local files > EasyAntiCheat > repair.
  3. Turn off any VPN on either player — it breaks the peer address the game hands out.
  4. Set the lobby to Friends-only to reduce churn while you reconnect.

Fixes that work for most Deep Rock Galactic errors

  1. Confirm both players are on the identical game build before troubleshooting anything else.
  2. Enable UPnP on the host router (or manually open the DRG UDP ports) to fix strict NAT.
  3. Repair EasyAntiCheat via EasyAntiCheat_Setup.exe in the DRG install folder, then reboot.
  4. Whitelist DeepRockGalactic.exe in Windows Firewall and antivirus on both machines.
  5. Disable any VPN — DRG's peer-to-peer join fails behind most VPN exit nodes.
  6. Join via the platform friends list rather than public matchmaking for a direct connect.

FAQ

Why can't I join my friend's Deep Rock Galactic game?

Usually strict NAT or a firewall block. Have the host enable UPnP, allow DRG through the firewall on both PCs, and join from the friends list.

How do I fix 'Connection to host has been lost' in DRG?

Have the host use a wired connection, disable any VPN, repair EasyAntiCheat, and set the lobby to Friends-only before rejoining.

Does Deep Rock Galactic need matching versions to play co-op?

Yes. After a patch both players must be on the same build or joins silently fail — update both, then retry.

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