If there are items in YellowDog but not in Connect or it doesn't have its corresponding barcode(s); you will need to intervene by manually initiating a sync of those items.
Verify all items not showing in Appetize have the required Publish and Merch settings.
- Right click on the item(s) from the main inventory items screen
- Select Trigger Item to Re-Sync to POS.
- This will flag the item to send updated information to Connect and the POS at the next sync.