NAT Type Is Probably Why Space Marine 2 Won't Let You Join Your Friends

You've assembled your squad, you're ready to purge xenos — and then the game won't let you connect. Space Marine 2's cooperative multiplayer is the heart of the experience, and connection failures between friends are among the most reported issues.

Start With the Basics

Confirm all players are running the same game version. A mismatch between patch versions is one of the simplest and most overlooked causes. Each player should check for updates through their platform's game library.

Next, verify the game servers are operational through official channels and community forums.

NAT Type: The Silent Connection Killer

NAT type is the single most common technical cause of multiplayer connection failures in Space Marine 2.

• Open NAT: Can connect to anyone. Ideal for hosting.
• Moderate NAT: Can connect to Open and Moderate.
• Strict NAT: Can only connect to Open NAT players. Severely limits who you can play with.

If you have Strict NAT and your friend also has Strict NAT, you cannot connect to each other.

How to fix: Enable UPnP in your router settings. If UPnP doesn't work, manually forward the ports used by Space Marine 2.

The Host Matters

Space Marine 2's multiplayer sessions depend heavily on the host's connection quality. Designate the player with the best connection as host. If the usual host has a poor connection, swapping hosts often resolves issues immediately.

When Local Fixes Aren't Enough

If you've confirmed NAT types are compatible, the host has a good connection, and background applications are closed — but you're still getting connection failures — the routing path between players is likely the issue.

GearUP Booster addresses this by optimizing the path between players, selecting routes that minimize latency and packet loss.

For console players, HYPEREV provides the same optimization through a hardware device that plugs into your network, controlled via mobile app.