Adding music to Ipod Shuffle gen 2

Apple Music subscription service tracks require an active subscription to work and cannot be synced to iPods that cannot validate the subscription like the shuffle.

You can transfer music your purchased from the iTunes Store, ripped from CDs or downloaded from other non-DRM protected sources to the Shuffle however.

That message indicates you are including some files it cannot play. Either because they come from Apple Music, or because they are in an incorrect format.

 The formats supported by the iPod shuffle second generation are: AAC (M4A, M4B, M4P) (up to 320 Kbps), MP3 (up to 320 Kbps), MP3 Variable Bit Rate (VBR), WAV, AA (audible.com spoken word, formats 2, 3, and 4).

Some of of the tracks you are trying to sync are not compatible. Make sure all are in the correct format. Specifically the one that was named there. There is something specifically wrong with that track.

Glad you sorted it out.