Make sure the Dome Cover or the Camera Lens is not polluted with contaminants.  (If it is, please clean and remove the contaminants.)

Please check the surrounding environment and the distance between the subject and the camera.  If the background is white then it can be really difficult to focus.

If it is having difficulty automatically focusing on a certain object, then the focus should be set to manual mode. 

Adjust the level of sharpness.