Mac and iTunes no longer recognizes ipod shuffle

All of a sudden, my iTunes doesn't see my iPod shuffle (2nd gen) anymore. It also doesnt appear on the desktop.

When I plug it in, the little orange light flashes, so it is charging. And the ipod itself still works.

I tried all the steps in this document, including updating iTunes and restarting my mac. I know the USB works because the iPod charges.

https://www.apple.com/support/ipodshuffle/assistant/itunes/#section_4

what can I do?