A common cause for a synced product to get out of sync is when a SKU has been updated sometime after a sync has been established.
Syncio uses SKUs to connect products, if this information doesn't match then inventory information between synced products cannot pass through.
Method 1: Unsync and Delete, then Sync Again
Use this method if you do not need to preserve customised information for a synced product on our destination store.
Go into Syncio, click into the Products section, choose the source store containing the affected product. Find the product and then click on the unsync button.
When the product has been unsynced and deleted from your store. Go into Syncio and sync over a new copy of the product. This new copy will now have the most up to date SKU information.
Method 2: Repairing the SKUs Manually, then Resync
Use this method if you need to preserve customised information for a synced product on your destination store.
It is possible to repair a sync by updating the SKUs on your product to match the source store's. A quick way to find the SKUs for both products is to use Syncio's Map button next to each product.
Search for the affected products on both source and destination stores and once you have both products side-by-side in the individual product mapper. Take note of which SKUs are not matching and then copy the new source product SKU information back into your product on Shopify.
Once your product's SKUs have been updated, use the resync button next to the product to reestablish the sync as soon as possible.