What causes players unable to connect through NAT?

Most players are behind NAT routers with no port forwarding, so a direct peer-to-peer connection cannot be established because neither side can reach the other's private address.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix Players Not Being Able to Connect (NAT)

Quick answer: Use NAT punchthrough with a signaling server, fall back to relay servers when punchthrough fails, and avoid requiring players to port-forward.

Players who cannot connect are usually blocked by NAT. Punchthrough and relays solve it without port forwarding. Here is how.

How to fix it

1. Use NAT punchthrough

A signaling or matchmaking server helps both peers open a path simultaneously (punchthrough), letting many NAT configurations connect directly without manual port forwarding.

2. Fall back to a relay

Some NATs (symmetric) cannot be punched through. Provide relay servers that both peers can reach, routing traffic through the relay when a direct connection fails, so connection always succeeds.

3. Never require port forwarding

Expecting players to configure their router is a non-starter for most. Build connectivity around punchthrough and relays so it works out of the box on home networks.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

The errors you never hear about are the ones quietly costing you players. Visibility turns them into a worklist.