CSV Import: Invoice > Error: Invalid item reference key xx.

Recommendations:

1. The CSV Import file should contain the same Item Name format as shown in Transactions > Sales > Create Invoices > Items tab > Items subtab > Item drop down field. 

2. Internal ID can also be used instead of Item Name. Just make sure that on the field mapping page, click on the pencil icon beside the Item field and Choose Reference Type = Internal ID.

3. Verify if the Item is Inactive. If the item record is inactive, set it to active status before importing.

-Navigate to Lists > Accounting > Items.

-Check the Show Inactives box.

-Uncheck the Inactive box beside the Item Name.

-Click on Submit.