Likely cause: Your wireless router may need to be power cycled, or the connection settings have changed.
How to fix: Power cycle your router; redo the connection settings on the Wii and try again.
Did this connection used to work but has suddenly stopped? "Power cycle" your router and modem. To do this, unplug both the modem and the router from the power outlet. Wait a few minutes, and plug the modem back in. Wait a couple of minutes for the modem to initialize, then plug in the router. Try to connect the Wii, Nintendo DS, or Nintendo 3DS online and test for proper response.
Erase your old connection settings on the Wii and set up a new one, as your router's settings may have changed since you last connected. We suggest following our guide to create a new connection file and start over. If at the end you still need help, you'll find contact information to reach our specially-trained representatives.