the back lit keyboard wont light up

on my new mbp, 3 days old, the keyboard wont light up. i press the back lit key on F6 and the bar comes up on screen with an x on it. i have 81% battery and i am on battery power. what is wrong?

Check in Preferences>Keyboard>Under Keyboard Tab

"Illuminate keyboard in low light conditions" is checked.

And check if the keyboard light works in dark.

thanks