Thank you Bob.That's what I did, yes. But contents didn't appear in the portal but nothing in AEM Preflight or in the production app.I tried and tried, and finally it succeeded... I can't understand why.More information today.

Same issue for me 2 days ago, and then it worked fine again.Until today. I juste migrated contents, placed them in collections then published. No contents appear in AEM Preflight or in the production app...Any idea?Maybe there's nothing to do but just wait til tomorrow?