iPhone cannot connect to Wi-Fi

[smudged]

So my first gen iPhone is able to see the network, but when I click on it, it just displays a check mark next to it and the signal bars go from half to full. When I hit the blue arrow next to my connection, every field is blank (IP, DNS) ect. My network is unsecured. Also there's also no SIM in the phone. Help please!

 

[speakerwizard]

does it have mac address filtering on? thats a common one.