Hi there, @LS20241. I want to ensure you'll able to map the items from Concur to your QuickBooks Desktop (QBDT).
To start, may I know the specific error you encounter when mapping items? That information is a great help so I can provide a timely solution.
In the meantime, I recommend reaching out to Concur support to further help you in correcting the mapping so items will be synced to your QBDT program without issue.
I also attached this helpful resource to provide additional information on how you can manage apps connected to QBDT: Set up QuickBooks Web Connector.
I'm always here ready to lend a hand if you have other concerns mapping items in your QuickBooks program. Have a good day ahead.