Explanation
What this error means
Error 2618-0516 appears in online games with the message that the NAT traversal process failed — the console couldn’t connect to the other player’s console. Nintendo notes it usually means your network isn’t well suited to the peer-to-peer connections online play relies on, typically because of your NAT type.
Official reference: Nintendo support page for 2618-0516
Diagnosis
Most likely causes
| Cause | How likely | Fixable at home? |
|---|---|---|
| Strict NAT type blocking peer connections | Very likely | Usually — router settings |
| Router firewall or settings too restrictive | Likely | Usually — adjust router |
| ISP-level NAT (CGNAT) limiting P2P | Possible | Sometimes — ask ISP |
| Game-server issue at the time | Possible | No — retry later |
Repair
How to fix it
Ordered easiest-first. Try the next step only if the error comes back.
-
Restart console and router
Restart the Switch and power-cycle the router — clearing a stale router state restores many connections on its own.
-
Check your NAT type
System Settings > Internet > Connection Status shows your NAT type. Type A or B is ideal; D or F means peer connections are being blocked.
-
Enable UPnP on the router
Turning on UPnP lets the Switch open the ports online play needs automatically — the simplest improvement for most home setups.
-
Set a public DNS
In Internet Settings, set DNS manually to Google (8.8.8.8 / 8.8.4.4) or Cloudflare (1.1.1.1) — a commonly suggested fix for this code.
-
Avoid double NAT
If a modem and a separate router both route, put one in bridge mode so only one device performs NAT.
Escalation
When it's not your fault
Signs the problem is on Nintendo's side — or in the hardware — rather than anything you can change:
- Connecting works on a different network (like a phone hotspot) but not your home Wi-Fi.
- The game itself reported server problems at the time.
- Your ISP uses carrier-grade NAT that limits peer-to-peer connections.
Questions
FAQ
What is NAT traversal?
It’s how two consoles behind home routers connect directly for online play. If your NAT type is too restrictive, that handshake fails and you see 2618-0516.
How do I improve my NAT type?
Enabling UPnP usually helps most; failing that, forwarding the game’s ports and removing any double NAT. Type A or B means you’re in good shape.
Is it the game or my network?
If it happens across multiple games and improves on another network, it’s your NAT. If it’s one game with reported server issues, wait it out.