Minecraft does not allow the marketplace, play with friends, on Realms, or on servers, despite Mario Maker working (which shows I have WiFi and a Nintendo Switch Online membership). I do connect to my Microsoft/Nintendo account fine. The only problem is multiplayer. For Realms it says, "We could not connect to Realms right now. We will try again soon" For friends it says' "We could not connect to Realms right now. We will try again soon" and "Your friends are not playing Minecraft right now." Servers says, "Coming soon." The marketplace says, "We're undable to connect to the Marketplace. Maybe check your internet connection?"

FIX: sign in and then out of your Microsoft account