If you have one email address with SellerZen and a different email with Intuit, then you'll need to add your QuickBooks Online company through SellerZen.
Sign into your SellerZen account. Click on Integration and add your QuickBooks Online company through the button.
Sign into your QuickBooks Online account using the email address you want to connect.
If you have multiple companies associated with your email address, select the one you want to connect to SellerZen. Otherwise you'll get the next Connect screen.
Confirm that the correct company is selected.
When ready, click on Continue to connect your QuickBooks Online company to SellerZen.
You'll have to connect your Amazon account afterward to configure your marketplace settings.