Is the red power led on, on the front of the antsle?

Is your ethernet cable plugged into the correct ethernet port?: 

Is there a link light on the ethernet port and switch?

Are you connected to the same subnet (same switch or vlan) as the antsle?

Does your computer resolve the .local domain name to an IP address? Test with a ping

The antsle's name is 'myantsle' by default but can be changed to a name of your choice.

    ping myantsle.local

    or

    ping antsle_name.local

Windows does not resolve .local names by default. You may need to install Bonjour print services for Windows or iTunes: 

If you get google search results instead of antMan you may need to use 'http://' in the url

    http://antsle_name.local/

antMan is listening on port 3000, try

    http://antsle_name.local:3000/

If you know the IP address of the antsle, you can open antMan with:

    http://x.x.x.x:3000/

You can find the IP address by connecting a keyboard and monitor to the antsle and login as the root user.  At the command line, run:

    ifconfig br0

The avahi service (mDNS) on the antsle is what advertises the .local names.  It uses IP multicast address 224.0.0.251 and udp port 5353.  Any chance you have a firewall blocking on your workstation or your router?