Why isn't the group name displaying as the text?

Hey there, Valiux!

The first thing to consider is that server scripts really should not run on the client. It's bad practice, and will not work correctly (if at all) under many circumstances. The client and server should never be intertwined, though that's a subject for another day. Let's jump into the solution:

We will make two scripts. One local script to change the GUI's text, and another server script to tell the local script when to do so. For the sake of cleanliness, I'm going to make another special type of script, called a Module, to store the admins. Observe:

The module, named Admins

-- The module. Let's assume you put it in ServerStorage.

--[[ A list of players that have admin privileges. The format is as follows:

    ["USERID"] = true;  -- The username of the player, for clarity.
    ["USERID"] = true;  -- The username of the player, for clarity.
    ["USERID"] = true;  -- The username of the player, for clarity.
    ...
--]]

return
{
    -- I happen to know that your UserID is 36872500. Unlike your name, it never changes.
    ["36872500"] = true;    -- Valiux
};

The server script

-- Server script:

-- A list of admins. require() gets whatever content is returned by the module, in this case, the admins.
local Admins        = require(game.ServerStorage:WaitForChild("Admins"));

-- A remote event that will tell a specific player's client to change the GUI text.
local OnChatted = Instance.new("RemoteEvent", game.ReplicatedStorage);

local GroupService  = game:GetService("GroupService");

OnChatted.Name  = "OnChatted";

-- When an admin says "!raid GROUPID", this function will tell his client to change its text, and supplies the group name required.
game.Players.PlayerAdded:connect(function(player)
    player.Chatted:connect(function(message)
        if (string.sub(message, 1, 6) == "!raid " and Admins[player.UserId]) then
            local groupID   = string.sub(message, 7);
            local group = GroupService:GetGroupInfoAsync(groupID);

            -- When we supply the player, we're just telling OnChatted which player we want to affect. Only the group name is actually sent.
            OnChatted:FireClient(player, group.Name);
        end;
    end);
end);

And finally, the client:

local OnChatted = game.ReplicatedStorage:WaitForChild("OnChatted");

-- When OnChatted is fired, change the text of rs.
OnChatted.OnClientEvent:connect(function(groupName)
    local text = "Raid Status: Official - " .. groupName;

    for i = 1, #text do
        -- I implore you to name 'rs' something more descriptive...
        script.Parent.rs.Text = string.sub(text, 1, i);

        wait(0.1);
    end;
end);

All right! I think I got everything. Give this solution a try, and let me know how it works for you. If there are any mistakes I made, do let me know. Have a nice day, Valiux, and best of luck with your game!

Warm regards, tkcmdr