Little more was missing

For a beginner like me, this flash is perfect. Combined with a D90 and a 50mm 1.8, it allowed me to take good pictures during this festive period and to avoid having "just the shiny head and the rest of the dark picture" obtained with built-in flash.
The flaw he: before taking the picture, the red part (above the Nikon) lights, suddenly, it failed to do in discretion, I do not know yet if it is possible disabled at no.