When you refresh items in The Order Exchange it sometimes end up with below error message;

Violation of UNIQUE KEY constraint 'UX_Item_ItemCode'. Cannot insert duplicate key in object 'dbo.Item'. The duplicate key value is (77d8a32c-af72-4a34-8020-a7825ca34f9e, 11ZZ904)

The first value 77d8a32c-af72-4a34-8020-a7825ca34f9e is supplier ID and 11ZZ904 is Item code

This happens when two items have the same barcode, or when users try to switch barcodes between items. 

This can be corrected by deleting the particular item code from TOE database item table

(Delete from item where itemcode ='11ZZ9040') and then by doing an item refresh.