I had to untick icloudiCloud music library, close prefs, then reopen it and it started syncing again. Briefly it also let me right click a song and upload to iCloud music library, but that didn't seem to do anything
Edit:
- Click on iTunes
- Click Preferences...
- Uncheck "iCloud Music Library (yourappleidyourappleid)"
- Click "OK"
- Click on iTunes
- Click Preferences...
- Check "iCloud Music Library (yourappleidyourappleid)"
- Click "OK"