Error code 6000 Business validation error you need to activate this item before updating the quantity
The items need to be marked active in QuickBooks, to sync the product or order.
While posting an order from Webgility Online if we enable the below settings then the item will be automatically marked active if it is inactive in QB.
Navigate to Settings> Accounting
Enable the option to Change Inactive items to active when posting orders
Click on Save
How do I make an inactive product active in QuickBooks Online?
You can still reactivate an inactive product or service if you need to restore it.
Go to Settings ⚙, then select Products and Services.
Select the Filter icon.
From the Status ▼ dropdown menu, select All.
Find the product or service that you want to reactivate.
In the Action column, select Make Active.
Note: While Syncing products it is required to mark items active in QB before syncing.