My AT3 suddenly lost its connection to the wifi (airport)

It cannot find it, even after resetting the AT and the airport (keep in mind the airport still works fine, everything else connects fine we've now connected directly through Ethernet, but the wifi will need to be fixed because having a cable running through the lounge :/ also that means the ipad remote app doesn't work

Has anyone else encountered this problem? Any clues on how to fix it?