SP2 can't find 5 Ghz network

[Tsurugaya]

Never had any problem connecting to the 5 Ghz SSID on my home network. Then I got the docking station and connected through cable, but I don't want to charge the SP2 all the time but when I turn off the charger I lose wired connection but suddenly I can't connect to the 5 Ghz only the 2.4 Ghz.
Other devices connect fine.