I have clicked “Save & Publish”, and the status toggle in the dashboard (purple color) indicates that the campaign has been successfully deployed – but my ad is still “Under Review” in Facebook Ad Manager.

Facebook & Instagram will manually review all ad’s creative, to ensure policy compliance. Your ad will only be published after review is successfully completed. The review process might take anywhere from 12-72 hours. New ad account will undergo more rigorous review, and may take longer before approval is granted. We recommend that you deploy your campaign at least 48 hours before your actual start date. Read here for more information.