Have you added Vendors to DX1 since coming onboard with DX1?  Use the following process to sync those vendors within the DX1 application and QuickBooks.

Within the accounting application click QB SYNCHRONIZATION on the left hand navigation menu.

Click the Vendors tab. Users can search for the vendor that was added from DX1. 

Users may click the drop down to Copy to Quick books or click  the Copy All checkbox.   Once all vendors have been chosen to be synced over click Submit in the upper right hand corner          

The sync progress window displays. Once the sync is complete it will indicate 100%.

Click Completed.