[Why can't I connect to Second life via Wifi, but I can connect via Ethernet cable?]

When I try to connect via Wifi it says
" Login Failed.
Second Life cannot be accessed from this computer.
If you feel this is an error, please contact
support@secondlife.com ."

but, when I connect via Ethernet Cable  its perfect;

plus I don't like connecting to Ethernet cable &* its not always avabiable for me to do so.
Plus I rather sit in my room or somewhere else, then sitting in one conner of my house just to be on Second Life