Okay today i played some pokefind (pokeworld) and after 30 min or so i got kicked saying "Disconnected" then i tried to join pokeworld again it says: "disconnected" so i was like huh it may work later when i came back now i have the same problem it is like someone kicks me EVERYTIME i try to join Pokeworld
That issue happened to me also, to fix it I suggest that you should restart your launcher with an older version of Minecraft such as 1.12.2 instead of 1.12.