I keep getting the error attempt to call string value?

Whenever I invoke this function, when I recieve the string from the server i just get the error attempt to call a string value twice.

Server Script:

function Filter()
    if game.ServerStorage.Summarizer.Value == "" then
        wait (16)
    end
    print ("2")
    local sumname = game.ServerStorage.Summarizer.Value
    local summarizer = game.Players[sumname].UserId
    local TextService = game:GetService("TextService")
    local filteredMessage = ""
    local summary = game.ReplicatedStorage.Summary.Value
    local success, errorMessage = pcall(function()
        local filteredMessage = TextService:FilterStringAsync(summary, summarizer):GetNonChatStringForBroadcastAsync()
    end)
    if success then
        return filteredMessage
    elseif errorMessage then
        print("Error filtering message:", errorMessage)
    end
end 

game.ReplicatedStorage.Filter.OnServerInvoke = Filter()

Local Script:

function SetSummary()
    script.Parent.Text = game.ReplicatedStorage.Filter:InvokeServer()
end

game.ReplicatedStorage.OpenVoting.OnClientEvent:Connect(SetSummary)

Thanks in advance!