DropBox, an online data storage system, requires login credentials for access. The sync tool cannot bypass this feature to access files. Therefore, the sync will not be able to connect with a QuickBooks company file that is hosted in DropBox.
The file needs to be with an actual hosting provider or on a computer or network to work with the Quickbooks Desktop sync tool.
If you do not see the described feature available in Bill.com, you may not have access to the feature based on permissions for your role and/or your plan does not have this feature. If you wish to get access to the feature, please review the available plans for Bill.com and upgrade accordingly or contact the Administrator of your Bill.com account. Changes in monthly user fees may apply.