So, you have an Ethernet cable. You connect it to WD Media Player, that media player can connect to the internet. Same cable, you pull and connect to Mede8er and Mede8er can’t connect to the internet. Is the preceding description correct?
If so, you could try pulling the power cord from the Mede8er, waiting 30 sec, plugging it back in, making sure the Ethernet cord is seated correctly (clicks into place) and trying again.