Snap deploy server and DHCP

When target PC boots from a CD (starting agent) or Network (over PXE) I always receive an IP address with 169.......On my network I have DHCP and I can see that target computer has received IP address from DHCP (address lease), but when starting agent on target PC i must add IP address manually every time.So I don't understand, DHCP works fine, but seams to me that is problem between deploy server and target PC. I can't figure it why!!!
Please help, thanks

 

i found what was the problem, i had to turn off the spanning tree on my switch!!!
now everything works!