If you change a template and approve that change, it will make any landing pages based on that template go into draft mode. You would then approve those landing pages in order to see the changes to the template reflected in the published page. Have you approved both the template and the page?
Thanx a lot for your answer !
You are right, when I change and approve my template, Marketo creates a draft. Then I have to modify it in order to see changes (when I only click on preview page on my draft landing page, changes haven't been applied), and approve it.
Thank you very much, it will save me a lot of time !