Unity C# - Tuple must contain at least two elements - error

Question

I am trying to update discord activities while playing my game in unity by DiscordGameSDK. I am weak in this area, so I admit that I copied everything from the guide, but I got stuck with this error:

CS8124:

---

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Discord;

public class DiscordManager : MonoBehaviour
{
    Discord.Discord discord;

    public static DiscordManager Instance;

    private void Awake()
    {
        if(Instance == null)
        {
            Instance = this;
        }
        else
        {
            Destroy(this);
        }
    }
    private void Start()
    {
        discord = new Discord.Discord(1317541816798806167, (long)CreateFlags.Default);

        UpdateRichPresence();
    }

    public void UpdateRichPresence()
    {
        ActivityManager activityManager = discord.GetActivityManager();
        Activity activity = new()
        {
            Details = "Playing Adventure Masters",
            State = "In main menu"
        };

        activityManager.UpdateActivity(activity, (res) =>
        {
            if(res == Result.Ok)
            {
                Debug.Log("Ustawiono status");
            }
            else
            {
                Debug.LogError("Nie ustawiono statusu Discord");
            }
        });
    }
    private void Update()
    {
        discord.RunCallbacks();
    }

    private void OnDisable()
    {
        discord.Dispose();
    }
}

I reaserched something in the internet but I didn't find anything helpful. On the official unity Discord server someone told me it's probably a syntax error.