Parameters in Remote Event not passing correctly?

Background: I'm making a Holo training facility for a group I'm in and this is part of it's commands. The command is to display a message (like admin scripts) on every player's screen Gives me this error: 15:48:29.964 - Unable to cast value to Object

The game has Experimental Mode off

Server Script:

game.Players.PlayerAdded:connect(function(player)
    player.Chatted:connect(function(msg)
		if game.Players:FindFirstChild(player.Name):GetRankInGroup(3207228) > 14 then
			if msg:sub(1,3) == "/M " then
				local filteredText = game.Chat:FilterStringForBroadcast(msg:sub(4), player)
				
				game:GetService("ReplicatedStorage").Message:FireClient(filteredText)
		    end
	    end
    end)
end)

There's a Remote Event in Replicated Storage that the Server Script fires, and in return a local script in PlayerGui copies a pre made 'template' gui and changes the text and makes it visible.

Local Script in Player's PlayerGui

game:GetService("ReplicatedStorage").Message.OnClientEvent:connect(function(filteredText)
	local a = script.Parent:FindFirstChild("Template"):Clone()
	a.TextLabel.Text = player..": "..filteredText
	a.TextLabel.Visible = true
	wait(5)
	a:Remove()
end)

Any help would be appreciated.