https://thenextweb.com/gaming/2018/06/13/sony-blocks-fortnite-players-from-transferring-progress-to-nintendos-switch/

Nintendo surprised gamers by offering up Fortnite on the Switch the same day they officially announced it. Some gamers were shocked and dismayed to find they weren’t allowed to play it on their portable consoles unless they created new accounts.

The details: The game was released on the eShop shortly after the Nintendo Direct where it was announced, and naturally users rushed to play it. But anyone who’s played the game on their PS4s at any point got a nasty surprise: an error message warning them their Epic Games account wouldn’t work.