Exception: System.NullReferenceException Message=The current Activity can not be detected. Ensure that you have called Init in your Activity or Application class.

Where I’m getting this issue: While hitting the API using httpclient as below

var content = new StringContent(jsonData, Encoding.UTF8, "application/json");
var response = await _client.PostAsync(uri, content);

Please help me with your suggestions

Environment: .NET 8, Android, MAUI, Visual studio.

Situation: I upgraded the Android Xamarin (.NET Framework) application to MAUI.

MainActivity Class:

[Activity(Name = "Test.MainActivity", Label = "Test Mobile", Icon = "@drawable/icon"
    , LaunchMode = LaunchMode.SingleTask, MainLauncher = true, ScreenOrientation = ScreenOrientation.Portrait, Theme = "@style/Maui.SplashTheme"
    , ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
public class MainActivity : global::Microsoft.Maui.MauiAppCompatActivity
{
    internal static MainActivity Instance { get; private set; }

    // for FCM push notifications
    internal static readonly string CHANNEL_ID = "fcm_notification_channel";
    internal static readonly int NOTIFICATION_ID = 100;

    enum EnvCheckType { Root, Debug, Emulator, Hooks, CustomFirmware, IntegrityCheck, WirelessSecurity };
    static BitArray envChecks = new BitArray(7);

    private MyBroadcastReceiver mMessageReceiver = new MyBroadcastReceiver();

    protected override void OnCreate(Bundle savedInstanceState)
    {
        try
        {
            Instance = this;

            base.OnCreate(savedInstanceState);
        }
        catch (Exception ex)
        {
            ExceptionLogger.LogErrorAsync(ex);
        }
    }
}

MainApplication:

[Application]
public class MainApplication : MauiApplication
{
    // for FCM push notifications
    internal static readonly string CHANNEL_ID = "fcm_notification_channel";
    internal static readonly int NOTIFICATION_ID = 100;

    enum EnvCheckType { Root, Debug, Emulator, Hooks, CustomFirmware, IntegrityCheck, WirelessSecurity };
    static BitArray envChecks = new BitArray(7);

    public MainApplication(nint handle, JniHandleOwnership ownership) : base(handle, ownership)
    {
    }

    protected override MauiApp CreateMauiApp()
    {
        var builder = MauiApp.CreateBuilder();
        builder.UseMauiApp<App>().UseMauiCommunityToolkit();
        
        return builder.Build();
    }
}

I tried making multiple changes regarding the Mainactivity and HttpClient but nothing worked