Wii Error Code 50400-50499 - Wii Error Codes

This error is caused by improper installation of the Wii LAN adapter.
To solve this error :

Ensure you are using a Nintendo LAN adapter as non-Nintendo LAN adapters are incompatible with the Wii console.
If you are not using the Wii LAN adapter, your internet connection settings for connection type should not be "Wired." If "Wired" is selected, erased this internet connection setting, start over, and select "Wireless" or "Nintendo Wi-Fi USB Connector."