Impersonate logged in user

Question

I am running as admin and I have no idea why this code is not allowing me in Impersonate a logged in user. I am trying to run this in powershell. I can not see my typo in this code.

# Specify the username of the account you want to impersonate
$usernameToImpersonate = "TestUser"

# Create a LogonUser signature
Add-Type @"
    using System;
    using System.Runtime.InteropServices;
    public class MyLogonUser {
        [DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
        public static extern bool LogonUser(string lpszUsername, string lpszDomain, string lpszPassword, int dwLogonType, int dwLogonProvider, out IntPtr phToken);
        [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
        public extern static bool CloseHandle(IntPtr handle);
    }
"@

# Logon to the system without a password
$token = [IntPtr]::Zero

$success = [MyLogonUser]::LogonUser($usernameToImpersonate, $null, $null, 3, 0, [ref]$token)

if ($success) {
    # Impersonate the user
    $impersonationContext = New-Object System.Security.Principal.WindowsIdentity($token).Impersonate()

    # Now you are impersonating the user

    # Perform actions as the impersonated user here

    Whoami

    # Revert the impersonation
    $impersonationContext.Undo()

    # Close the token handle
    [MyLogonUser]::CloseHandle($token)
} else {
    Write-Host "Failed to log on to the user account."
}