Typically if a sync is not working there are some common setup issues. Can you please confirm the following:
1. Navigate to Inventory > Inventory Management> All inventory and click the binoculars icon to open up the product detail screen for the SKU that is not syncing. Choose the Green 'Manage Listings' button, and then the green icon next to 'Channel Setting . Does the reference ID for each sales channel matches the SKU on the sales channel?
2. Can you confirm on the sales channel itself such as eBay, Amazon, Shopify, etc that the Custom Label or Merchant SKU is setup to match the ecomdash SKU? (Within eBay, we use the custom label value to make a match on the SKU number within ecomdash)
3. Can you confirm you have turned on Auto Sync for the product and you see a blue icon next to the SKU? Navigate to Inventory > Inventory Management>All inventory to view the blue icon next to your product SKU's. If auto-sync is turned off, we will not send a sync update.
4. If you click on the movement tab by navigating to Inventory>Inventory Management> All Inventory -> click the binoculars icon for your product > choose the link 'View Movement History' in the Inventory section do you see transactions that have occurred since you enabled auto sync that would have triggered a sync?
5. If you go to Inventory > Inventory Management>All Inventory and select the product and take the “Sync Now” action located within the sync actions, does that push update the sales channel?
To check any syncing issues, navigate to Inventory > History > Sync Inventory History. This screen will display your SKU number and sales channel with any errors that might have occurred.