2124-4025 blocks online play when Switch cannot reach Nintendo servers or NAT type is too strict.
Server or clientUpdated 2026-06-11
NAT Type and 2124-4025
Open NAT (Type A or B) helps online play. Type D or F often triggers 2124-series errors in multiplayer titles.
How to fix step by step
- 1Check Nintendo Network status.
- 2Test connection: System Settings → Internet → Test Connection.
- 3Restart Switch and home router.
- 4Enable UPnP or set Switch port forwarding on router.
- 5Move closer to router or use 5 GHz Wi‑Fi.
- 6Update Switch system software to latest version.
How 2124-4025 differs from related codes
- Error 2162-0002: Switch cannot read or write to microSD storage. (usually client-side)
- Error 2813-2470: Nintendo eShop could not load. (server or client)