Make sure your latest code and content is in the live environment
Use the Pantheon dashboard tools to ensure your live environment is ready to launch, with your latest code and content. Have your stakeholders review the site content before launch. If a third-party vendor developed your site, make sure that you or a member of your department is the official Owner of the site on the Pantheon dashboard.
Pantheon help page:
Launch Essentials Add All Domains on your Site Dashboard
Add your production domain(s) to your...