I think I heard something recently about making sure the place you are teleporting to has some kind of permission turned on.
Can’t be sure where the setting is though.
try to use TeleportAsync instead.
also make sure that Allow Third Party Teleports is set to true.
local repStorage = game:GetService("ReplicatedStorage")
local tpEvent = repStorage:WaitForChild("tp")
local tp = game:GetService("TeleportService")
tpEvent.OnServerEvent:Connect(function(plr)
tp:TeleportAsync(10456225557,{plr})
end)