Once you have connected your Jackrabbit database to your QuickBooks account (Connect Jackrabbit to QuickBooks Online - The 1st Step) you will need to assign an account from your QuickBooks Chart of Accounts to each of your Jackrabbit Category 1s. These accounts are where all of your revenue will be posted when you bring in the export from Jackrabbit.
From the Gear (menu) > Tools > QuickBooks Export select Assign/Edit QuickBooks Accounts (left menu).
The first line in the Category1 column is blank; this is intentional. When a payment in Jackrabbit is not matched to a fee(s) it is considered uncategorized income (i.e. has no Category1). Assign the blank field a QuickBooks account that will draw your attention to the need to allocate these amounts to a revenue source.
From the drop-down in the QuickBooks Account:Subaccount column select a QuickBooks revenue account for each Category1.
The drop-down options were populated when you first connected Jackrabbit and QuickBooks and include ALL accounts in your Chart of Accounts, not just revenue accounts. Ensure you select a revenue account and not an asset, liability, or expense account.