https://www.gamespot.com/articles/playground-mode-in-fortnite-is-down-but-set-to-com/1100-6460056/

Update 3: The latest from Epic doesn't change the expected return of Fortnite's Playground, but it also doesn't sound as if its release is imminent. An update to the same Reddit post states: "We're continuing to test improvements made to our matchmaking services for the Playground LTM. We want to get you out there and let you unleash your creativity but also want to ensure a positive experience once we enable this game mode again. We'll give you more updates and a timeline as soon as we have one."

Update 2: Epic has provided another update on the status of Fortnite: Battle Royale's new Playground mode. In another Reddit post, it stated, "Yesterday we launched the Playground LTM. So many of you rushed in to create and play that our matchmaking service fell over. We've since separated the Playground matchmaker from the one that affects the default modes and made large improvements to assist with the number of players. We plan to push these changes and improvements live later today to bring the Playground LTM back online. We'll give you more updates and a timeline as soon as we have one."