Yongnuo speed light

manu99

I have a YN 468 ii speed light. It doesn't seem to work in the iTTL mode. The flash fires, but the picture is badly underexposed. Using the pop up flash on the D5200 gives much better results. Also the infrared focusing light doesn't work. I have tried it on the spot focus mode as I have been advised, but no luck.
Has anyone else had these problems?
Thanks.