In my experience, it is always a good idea to make sure of the following:
Make sure the device (radio/board) plugs straight into the PoW and then into the switch on the uplink port or a normal switching port, it all depends on the setup. (Just in case you are new
)
After that, if you are still not getting a link light, the problem may be as simple as a bad cable or a bad port on the switch. Technically there shouldn't be a problem connecting to a switch and getting a link light unless it is a smart switch and the port is disabled.
*Technically* This should be a simple problem to fix... "technically"
Hope that helps