You need to claim a website before you can advertise products via Google Merchant Center. Will AdNabu help in this?
AdNabu will try to automatically claim your website in Google Merchant Center. However, If you have already claimed the URL in another merchant center, you might have to manually reclaim the website.
The option to claim the Merchant center is in the account setup of onboarding.
If you want to try claiming the website after initial onboarding, you can choose to do so from settings > merchant center settings from our app