This error indicates that the TFTP transfer has timed out.

Things to try:
  * Make sure you are using the correct server address.
  * Check that the TFTP server is online and responding to requests.
  * Check that your IP configuration is correct.  You can use the iPXE command ''route'' to show your local IP address, subnet mask, and default gateway: <code>  iPXE> route
  net0: 10.0.0.162/255.255.255.0 gw 10.0.0.1</code>
  * running ''tcpdump -s0 -vvv -i eth0 ether host [iPXE client mac]'' on the tftp server will show if the requests reaches the machine or not