Once you migrate your legacy account to Epic Games account, all your remaining PPI credits and licenses for already paid inputs will be transferred as well. In order to use them, you need to sign in with Epic Games accou…
https://dev.epicgames.com/community/learning/knowledge-base/pq58/capturing-reality-cannot-export-my-model-in-ppi-mode-after-migrating-to-epic-games-account