Solution
Is the camera moving when you press the shutter button?
Make sure not to move the camera when you press the shutter button.
Particularly, when shooting night scenes or shooting in dark surroundings, the shutter speed is slower than that under normal shooting conditions. Use a tripod or a remote controller (sold separately) to make sure that the camera remains still when shooting.
Is the distance between the lens and the subject within the lens's focus range?
The focus range within the distance from the lens to the subject differs depending on the lens. Check the type of the lens you are using and make adjustments to the distance between the subject and the lens.
Is the subject covered by the AF point in the viewfinder?
The camera focuses the subject that is covered by the AF point in the viewfinder.
If the subject cannot be covered by the AF point for reasons of composition, use the focus lock function.