Did you install the DHCP form the install script? If so, rebuild your server NOT using fog as the DHCP server. I can only assume that some settings are clashing.
If you want to have FOG dole DHCP that is fine but you won’t need DHCP.
If you want to use DNASMASQ to leave your DHCP setup alone and pxe boot via proxy dhcp, don’t install the dhcp, the two will clash settings.
We would be willing to help you to troubleshoot your issues, but you need top choose a path and stick to it. I would start by commenting out the line
“pxe-service=X86PC, “Boot from network”, undionly” some networks don’t need to be told to boot, and some do.
Are you not able to edit your DHCP settings to include your FOG server and Boot file name?