Check that your password matches the password you have in your wireless router.
For a Windows-based PC, here is one way you can check this.
Note: This does not apply for MAC OSX because their operating system is completely different.
Step 1. On the task bar at the bottom right-hand corner of your display, right click on your wireless icon, which should look similar to this:
Step 2. Click Open Network and Sharing Center.
Step 3. Move your mouse over the Wi-Fi xx (Name of Your Connection/SSID) and click.
Step 4. When the Wi-Fi status dialogue box pops up, click on Wireless Properties.
Step 5. Another dialogue box will pop up with your network properties. Click on Security and tick the Show characters checkbox for your password to appear in the Network security key box.
Step 6: Once you confirm the password, make sure it is the same password you are entering on your controller by going to Settings > Wireless > Password:
The password is case-sensitive, so it must match exactly.
Reminder: Make sure you are connected to the right wireless network. If you don't know what your wireless network password is and you're using a Mac (or are unable to follow these steps using Windows), contact your ISP.