HOW TO FIX THIS ERROR MESSAGE.
Here is how you can view your sync errors: View Sync Log
How to view error messages on the Manage Account Website:
-From the Manage Account Website, click on Reports.
-Click Sync Reports.
-Click Sync Log.
-The top section shows the syncs you have run. Click on the most recent date.
-The bottom section shows the details of the sync. Errors are in red and notices are in green, so it's easy to -scroll through and see what the errors are.
SYNC ERROR: Could not update the information for customer. Details: The name "Josh Smith" of the list element is already in use.
This error message isn't all that descriptive, but what it means is that we have a link to your customer Josh Smith in your QuickBooks, but either this customer doesn't exist any more or it is inactive or it has been merged with another customer.
If this customer has been inactivated, please reactive him in your Quickbooks.
That should resolve this issue.