Ethernet Weirdness

[absolutk]

LOL... Mute is not on....  FMC = ?

FMC = Fiber Media Converter - the TP Links devices that take ethernet on one device use fiber to connect to another device, which outputs ethernet again, thereby isolating any electrical noise from the ethernet.

Few other things to check:
1) try a different ethernet cable (even if an inferior one). Sometimes the termination jiggles around making an unreliable connection
2) Keep the rightmost button on the remote pressed till you enter the diagnostic screens on the Dev, then repeatedly press it till you see the two vertical green/orange bars that show signal amplitude. Make sure that's showing an input signal when music is playing. That helps you decipher is the issue is between PC and Dev or Dev and speakers
3) I've messed this up once before - make sure you are connecting the speakers to the right binding posts, since it's easy to use the wrong ones. Step 2 should show dancing bars if this is the case.