Sync products/items between Books & CRM not importing stock levels

Sync products/items between Books & CRM not importing stock levels

I have used the Books Connect - Products in Zoho CRM to sync between Books and CRM but stock level information is not being synced - Qty in stock, Qty ordered & Qty in demand are all showing as 0 even though this info is available in Books. 
In other words there is no sync happening.

How do I make it work?