This script gives me plr is a nil value?

local Players = game:GetService("Players")
groupID = 3237760
rankID = 10
local TweeenService = game:GetService("TweenService")
local door1 = script.Parent:WaitForChild("Door1")
local door2 = script.Parent:WaitForChild("Door2")
local tweenfor = TweenInfo.new(

    0.5,
    Enum.EasingStyle.Linear,
    Enum.EasingDirection.Out,
    0,
    false,
    0
)

local door1Open = {CFrame = CFrame.new(-78.9, 4.1, -164.2)}
local door2Open = {CFrame = CFrame.new(-78.9, 4.1, -172.45)}
local door1Close = {CFrame = CFrame.new(-78.9, 4.1, -167)}
local door2Close = {CFrame = CFrame.new(-78.9, 4.1, -169.75)}
local tween1open = TweeenService:Create(door1,tweenfor,door1Open)
local tween1close = TweeenService:Create(door1,tweenfor,door1Close)
local tween2open = TweeenService:Create(door2,tweenfor,door2Open)
local tween2close = TweeenService:Create(door2,tweenfor,door2Close)

script.Parent.Detector1.Touched:connect(function(hit)
    local plr = Players:GetPlayerFromCharacter(hit.Parent)
    if plr:GetRankInGroup(groupID) == rankID then
        tween1open:Play()
        tween2open:Play()
        wait(2)
        tween1close:Play()
        tween2close:Play()
    end
end)

script.Parent.Detector2.Touched:connect(function(hit)
    local plr = Players:GetPlayerFromCharacter(hit.Parent)
    if plr:GetRankInGroup(groupID) == rankID then
        tween1open:Play()
        tween2open:Play()
        wait(2)
        tween1close:Play()
        tween2close:Play()
    end
end)

Located in a model, server script.

What this script does is it makes a sliding door open if a player is an admin in a group. It gives me an error saying the plr is a nil value. Any help would be appreciated!