see the raw file attached. it is not good clear. if i use nikon capture or photoshop Camera Raw to enhance image proper to make tiff still it shows blur on all round edges to innerward some area.
I took a look at your .nef/raw file and noticed you are using "spot" metering this will be your issue. Using spot metering your focus range is small and most likely will alway focus at the centre of the image. You need a wider focus setting. Also a slightly higher aperture will help you out F/5.6 I personally would be using F/8.0 to F/11.0
Read the manual on how to set the metering. You want focus on all areas not just the centre spot. I do not own that model camera so I cannot offer more assistance.