Here are some of the issues that you might notice:
(1) Check if the C-CS adapter is on the thread. This is a CS-Mount camera so if you forget to move the adapter off, it won’t be able to focus. To check that, make sure your camera looks like the following where the focus ring with the fix screw is right above the back focus adjustment ring.
(2) Notice the order when you are adjust the lens. The following steps is recommended:
i. unscrew the fix focus handle on the focus ring
ii. adjust the focus ring until you reach the best sharpness you can, regardless of whether it’s in focus. Then spin/screw the focus handle to fix it.
iii. unscrew the back focus lock screw.
iv. adjust the back focal adjustment ring back and forth until you get a best sharp image. Then screw the back focus lock screw.
v. fine tune the focus ring again if necessary.