The “Account” field on the System > Setup Tables > GL Accounts table in Manage must be consistent with the “Name” field on the Company > Chart of Accounts > Account screen in QuickBooks Online.
Note: the fields are case-sensitive and values should match exactly.
Note: Accounts will not be automatically created in QuickBooks Online if they are not found. An error message will be raised when attempting to push transactions.
It is important to note that any time that you make changes to your GL Account Mapping you need to open and then close any closed invoices that use that mapping for it to change. Once you have done that you can then successfully run the batch in QBO to show the new account. More on this here.
Since the Account Number field is optional, QuickBooks Online uses the Account Name as the primary key. As a result, the Account Number should never be included in any mappings within Manage.