Ubuntu with network manager can be really picky. Most times, I have to set a static IP if I'm not given one, just to make NM see that its connected.
First, see if avahi can see other devices on the network
If not, try setting a static IP address on a new network connection in Network Manager. To make it simple, use Ethernet for now. Select that new network when you connect the cable. Then test again.
Look for a couple of entries that start with roboRIO-4057 or grep for them.
Code:
avahi-browse -ar | grep roboRIO