The line usually means that your players aren’t up in the network yet while the server is already scanning. It just means your player is not found.
However, you say your sound card is at 0%. That means it’s not successfully recognized by the system. Check the HiFiBerry plugin again, select „none“, reboot, reselect your sound card and reboot.
Also, please clarify this line:
oIn the audioplayer I seke mehelpcted the sysdefault audiocard,