When attempting to publish a landing page to Facebook, you get the error "Error when calling Social Campaign API. Warnings: Error while creating facebook tab."
If you haven't purchased Ad Targeting add-on for your instance, you could face this issue. You can contact your Customer Success Manager to include this add-on in your Marketo subscription. If you are facing the issue in spite of having ad targeting add on to your subscription, we would suggest that you contact Marketo support and we will be able to troubleshoot it for you.