PS3 to Wifi

Hello,
When connecting my PS3 to Wifi, it doesn't connect.When I go to network settings. I press easy next, then press wireless when I want to select my connection method, then press scan, it then brings me to select my access point to be used,I then select my own, then I then select my WLAN security settings, then put in my WPA Key, then it tells me checking network configuration, before it will now tell me the attempt to obtain an IP address timed out. I still don't understand "the attempt to obtain an IP address timed out"