Hi Blackout.
Have you created a Pre Boot configuration, right? Go to "Settings > Deployment > Manage Preboot Configurations". In the new screen, create a new configuration and don't forget to choose the PXE Automation Type or both.
After that, wait your NS / Site Server receive the new policy and create the new Preeboot Image (You will see in the process tab the Bootwiz.exe running").
After that, stop and the PXE services ( Symantec Network Boot Service (PXE and BSPD) and Symantec Network Boot Service (TFTP). Then, test the machine again.
If you won't use the PXE, you can run the Bootwiz.exe and generate the boot image in a CD or Pen Drive. I'm attaching an article bellow that explains all the process.
https://www.symantec.com/connect/articles/steps-create-winpe40-through-boot-disk-creator-bdc-limited-support
Regards,