Please read the following seven steps to ensure that your inventory syncs properly.
Settings to be aware of in your Shopify admin.
Ensure that products needing to be synced have 'Track Quantity' ticked.
2. Product availability must have the ‘Online Store’ ticked to be visible on Syncio.
3. At least one image must be uploaded to a product to be visible on Syncio.
4. Each product/variant must have a unique SKU assigned. Syncio can auto generate unique SKUs when importing to a destination store if they don't exist.
5. When mapping an existing product, the product/variant SKUs in the Source store must match the corresponding product/variant SKUs in the Destination store.
6. Destination stores can only trigger an inventory update to the Source store through a fully paid order.
7. After syncing, do not change the SKU - this will not sync across to the other store and it will break the connection.