Are you sure you have your miner's ip address correct? You can use the program Advanced IP Scanner to scan for all devices on your network.
I'm guessing it would either be an incorrect IP like swilla mentioned, or that the router is on a different subnet than the Antminer is. If swilla's solution doesn't work, I'd recommend following
this guide and seeing if that fixes your issue. I had to follow it since my subnet is 172.16.x.xxx compared to the Antminer's default of 192.168.x.xxx, but it solved the problems I was having.