Client connected to broker but controller throws InvalidOperationException: The MQTT server is not started

[adamfierek]

Program.cs:

var builder = WebApplication.CreateBuilder(args);

builder.WebHost.UseKestrel(o =>
{
    o.ListenAnyIP(1883, l => l.UseMqtt());
    o.ListenAnyIP(5000);
});

var optionBuilder = new MqttServerOptionsBuilder()
    .WithoutDefaultEndpoint()
    .Build();

builder.Services.AddControllers();
builder.Services.AddHostedMqttServer(optionBuilder);
builder.Services.AddMqttConnectionHandler();
builder.Services.AddConnections();

var app = builder.Build();

app.UseAuthorization();
app.MapControllers();
app.Run();

StatusController.cs:

private readonly MqttHostedServer _mqttServer;

public StatusController(MqttHostedServer mqttServer)
{
    _mqttServer = mqttServer;
}
[HttpGet]
public async Task<IActionResult> GetConnectedClientsAsync()
{
    var clients = await _mqttServer.GetClientsAsync();
    return Ok(clients);
}

Line var clients = await _mqttServer.GetClientsAsync(); throws InvalidOperationException: The MQTT server is not started, but client can connect successufuly. Do I have two instances of Mqtt server in my app? How to do it in .NET 6? I saw documentation and samples for .NET 5 but I can't make it work.