QuickBooks Online Sync Error: Customer has a non-zero balance in QBO

Why the Sync Error occurs

This error occurs when a deleted customer in PayMaker is trying to sync to QuickBooks Online (QBO), but the Customer has an open/non-zero balance in QBO.

How to Fix the Sync Error

Reactivate the customer in PayMaker until the customer has a non-zero balance in QBO, or delete the customer's invoice(s) in QBO and sync.