QuickBooks Online Sync Error: Invalid entity data. Email: Invalid email format.

Why the Sync Error occurs

This error occurs when a customer is created in QuickBooks Online (QBO) and more than one email address is entered.

How to Fix the Sync Error

  1. Update the Email Address field for this customer in QBO, removing all but one email address
  2. Save

To prevent this error, enter only one email address for each customer when entering the customer details in QBO.