Although the manual does not have indicate a focus error, I assume you notice the camera can't focus correct.
I hope you know the camera has a focus selector, see the picture. (in the manual, page 10. For auto focus you should select C-AF (continues) or S-AF (single). If it is in manual, toy should focus yourself using the focus ring on the lens (closest to the camera)
Then to help the focus system, there is a external AF sensor. If it is dirty, then it is difficult for the camera to focus correct in a short time.
Also be aware the camera likes to have extra contrast on the focus distance and no objects in front of the subject you want to pictures, with lots of contrast.
Sometimes point to a object with a sharp contrast, on the same distance, press the shutter release button half, then reframe your picture and only then press the button complete.
when you want to shoot fast moving objects choose C-AF.
I hope this helps.