Hold down the On/Off button on the remote for over five seconds, when the set is on, and let it soft reboot.
if this does not fix it, try a Factory Reset.
if that does not fix it, you could contact Sony, or wait for the next software update, or hardwire the Ethernet (or at least use Powerline adaptors for a wired Ethernet connection).
or return the set whence you bought it, as faulty, and get a replacement.
YouView Superuser, but not an employee of YouView, nor retained by them for this purpose. It's purely me speaking
