Solution 1: Tinkering with your network configuration, router settings and learning why system and network administrators tend to hate the human kind.

there are actually two solutions most gaffers will suggest you. they are both pretty similar.

zamkato's solution

1. Navigate to the Wi-Fi portion of the System Settings menu.

2. Tap on or select the option to “Connect to the Internet”.

3. Press X on the GamePad to view your connections and delete every saved connection by tapping on it and opting to “Delete Settings”.

4. Once all connection settings are cleared, return to the “Connect to Internet” screen, select your WiFi network, go through the regular setup process and wait.

5. Once the setup fails – don’t worry, if you’re encountering connection errors, it most definitely will – power down both the Wii U console and GamePad.

6. Reboot the Wii U and return to the Connections portion of the WiFi settings (repeat steps one through three).

7. Tap on your saved Wi-Fi network, followed by “Change Settings”.

8. Enter your network’s SSID (the name assigned to your router).

9. Select the proper security type and input the router’s official password.

10. Change the “IP Address” option from “Auto-obtain” to “Don’t Auto-obtain”.

11. If you’re on Windows, launch cmd and type “ipconfig”. If you’re on OS X, navigate to the Network portion of the System Preferences app, highlight your Wi-Fi network, click “Advanced…”, followed by the “TCP/IP” tab (the “Router” number is used for the “Gateway” field).

12. Input your router’s IP address and add “10″ to the last digit (e.g. if the IP is “192.160.0.1″, enter “192.168.0.110″).
Note: In certain cases, exclude the “10″ – we recommend that you try both.

13. Enter both the Subnet Mask and Gateway (obtained in the eleventh step).

14. Tap “Confirm” and select the option to “Configure” once a DNS settings prompt appears.

15. Change the “DNS” option from “Auto-obtain” to “Don’t Auto-obtain”.

16. Type “4.2.2.2″ for the “Primary DNS” field and “4.2.2.1″ for the “Secondary DNS” field.

17. Tap “Confirm”, ensure that the “Proxy Settings” are set to “Don’t Use” and leave the MTU Value set to the default option (1500).

18. Press B to exit and save and press “Connection Test”.

That's a guide from NeoGAF I found, it seems to work, albeit a bit complicated.

Thanks for the effort but it didn't seem to work :(. Oh well maybe I just buy that Wii enthernet adopter. Hate sitting and do this stuff and that's why I always want enthernet port. Are all of them the same or is their one that is better?(Official? )

This ^

Def call Ninty with any issues you have.  They have always been great to deal with, on anything.  If you have issues, they will walk you through a fix.