Invalid entity data. Email: Invalid email format.
When clients create customers in QuickBooks Online, they will receive this error when more than one email address is listed for the customer in QuickBooks Online.
This error occurs when a customer is created in QuickBooks online, and more than one email address is listed.
To resolve this error, please update the email address field in QuickBooks Online, to include only one email address for the customer getting the error.
As a best practice, to avoid getting this error in the future, include only one email address for customers when entering them into QuickBooks Online.