DELL POWEREDGE T430 SERVER ?
Format your USB stick to UEFI and GPT by downloading the tool from :https://rufus.akeo.ie/. Start the tool as administrator. Select the USB storage device then make the partition scheme and target system type to be GPT “partition scheme for UEFI. Give it the ISO image of windows server 2016 or whichever O.S you are installing and let the tool create the bootable USB. In the server boot settings make it UEFI and then make the partition GPT.