Why do my Yamaha natural sound at receiver RX-v681 telling me to check the speaker wires?

[egumbs2526]

Why do my Yamaha natural sound at receiver RX-v681 telling me to check the speaker wires?

 

[jsmithepa]

Detected a short, an unusually low ohm-age. U maybe attempting to run 4 ohm speakers when receiver can only handle 8 ohm.