ERROR:
Could not find a UOM Group to associate with this item

EXPLANATION: 
Unit of measure assigned to item is invalid or does not exist in Sage Intacct.  

Creating item in Sage Intacct will produce error:

SOLUTION: 
In Sage Intacct, go to Order Entry > click Units of Measure
Create new Unit of Measure Group:

Edit item and update Unit of measure field
Run a sync