I am using Request Response Pattern for making sure that the proper work flow done sequentially, I have 3 Projects

Order.API
OrderPayment.API
OrderConfirmation.API

It is properly executing each Consumers, but after that, after last consumer’s last code, it give me loading on swagger and Every time it is throwing Request Time out error. , it is not returning response back to Controller wither successfull work done or not, it is going for wait and then response is Request Timeout Error

Code
Consumer In OrderPayment.API

public class PaymentConsumer : IConsumer<PaymentProcessed>
{
    public async Task Consume(ConsumeContext<PaymentProcessed> context)
    {
        Console.WriteLine($"Payment processed for OrderId: {context.Message.OrderId}");
        await context.Send(new OrderConfirmed { OrderId = context.Message.OrderId });
    }
}

and in Program.cs

builder.Services.AddMassTransit(x =>
{
    x.AddConsumer<PaymentConsumer>();
    x.UsingRabbitMq((context, cfg) =>
    {
        cfg.Host("localhost", "/", h => { h.Username("guest"); h.Password("guest");});
        cfg.ConfigureEndpoints(context);
    });
});

In OrderConfirmation.API

public class ConfirmationConsumer : IConsumer<OrderConfirmed>
{
    public async Task Consume(ConsumeContext<OrderConfirmed> context)
    {
        Console.WriteLine($"Order {context.Message.OrderId} has been confirmed.");
        await Task.CompletedTask;  
    }
} 

and in Program.cs

builder.Services.AddMassTransit(x =>
{
    x.AddConsumer<ConfirmationConsumer>();
    x.UsingRabbitMq((context, cfg) =>
    {
        cfg.Host("localhost", "/", h => { h.Username("guest"); h.Password("guest");});
        cfg.ConfigureEndpoints(context);
    });
});

Shared Models and States and Events

namespace SharedModels.OrderProcessModels
{
    // Event when an order is created
    public class OrderCreated
    {
        public Guid OrderId { get; set; }
    }

    // Response for Order creation
    public class OrderCreatedResponse
    {
        public Guid OrderId { get; set; }
        public string Status { get; set; } = "OrderCreated";
    }

    // Event when the payment is processed
    public class PaymentProcessed
    {
        public Guid OrderId { get; set; }
    }

    // Response after Payment is processed
    public class PaymentProcessedResponse
    {
        public Guid OrderId { get; set; }
        public string Status { get; set; } = "PaymentProcessed";
    }

    // Event when the order is confirmed
    public class OrderConfirmed
    {
        public Guid OrderId { get; set; }
    }

    // Response for order confirmation
    public class OrderConfirmedResponse
    {
        public Guid OrderId { get; set; }
        public string Status { get; set; } = "OrderConfirmed";
    }

    // State object that tracks the lifecycle of an order
    public class OrderState : SagaStateMachineInstance
    {
        public Uri ResponseAddress { get; set; }
        public Guid RequestId { get; set; } // Optionally store RequestId for correlation
        public Guid CorrelationId { get; set; }  // Unique identifier for Saga instance
        public Guid OrderId { get; set; }        // Order identifier
        public State CurrentState { get; set; }  // Current state of the order in saga
        public DateTime? CreatedAt { get; set; } // When the order was created
        public DateTime? PaymentAt { get; set; } // When the payment was processed
        public DateTime? ConfirmedAt { get; set; } // When the order was confirmed
    }
}

Now the Order.API I created OrderStateMachine.cs

public class OrderStateMachine : MassTransitStateMachine<OrderState>
    {
        public State PaymentProcessed { get; private set; }
        public State OrderConfirmed { get; private set; }
        public Event<OrderCreated> OrderCreatedEvent { get; private set; }
        public Event<PaymentProcessed> PaymentProcessedEvent { get; private set; }
        public Event<OrderConfirmed> OrderConfirmedEvent { get; private set; }


        public OrderStateMachine()
        {
            InstanceState(x => x.CurrentState);
            // Correlate Events with Saga Instance by OrderId
            Event(() => OrderCreatedEvent, x => x.CorrelateById(c => c.Message.OrderId));
            Event(() => PaymentProcessedEvent, x => x.CorrelateById(c => c.Message.OrderId));
            Event(() => OrderConfirmedEvent, x => x.CorrelateById(c => c.Message.OrderId));

            // Initial State -> PaymentProcessed
            Initially(
                When(OrderCreatedEvent)
                    .Then(context =>
                    {
                        context.Saga.OrderId = context.Message.OrderId; // Save the order ID
                        context.Saga.CreatedAt = DateTime.UtcNow; // Set the creation timestamp
                        Console.WriteLine("Order created, transitioning to PaymentProcessed...");
                    })
                    .TransitionTo(PaymentProcessed) // Move to PaymentProcessed state
                    .Publish(context => new PaymentProcessed
                    {
                        OrderId = context.Saga.OrderId
                    })
            );

            // PaymentProcessed State -> OrderConfirmed
            During(PaymentProcessed,
                When(PaymentProcessedEvent)
                    .Then(context =>
                    {
                        context.Saga.PaymentAt = DateTime.UtcNow; // Set payment timestamp
                        Console.WriteLine("Payment processed, transitioning to OrderConfirmed...");
                    })
                    .TransitionTo(OrderConfirmed) // Move to OrderConfirmed state
                    .Publish(context => new OrderConfirmed
                    {
                        OrderId = context.Saga.OrderId
                    }) 
            );
            //Final State -> Complete Saga
            During(OrderConfirmed,
                When(OrderConfirmedEvent)
                    .Then(context =>
                    {
                        context.Saga.ConfirmedAt = DateTime.UtcNow; // Set confirmation timestamp
                        Console.WriteLine($"Order confirmed for OrderId: {context.Saga.OrderId}");
                    })
                    .Finalize() // Finalize saga after order is confirmed
            );
            SetCompletedWhenFinalized();
        }
    } 

OrderController.cs in Order.API

namespace Order.API.Controllers
{
    [ApiController]
    [Route("api")]
    public class OrderController : ControllerBase
    {       
        private readonly IRequestClient<OrderCreated> _requestClient; //bcz wait for the first one, then execute further.
        public OrderController(IRequestClient<OrderCreated> requestClient)
        {  
            _requestClient = requestClient;
        }
         
        [HttpPost("PlaceOrder")]
        public async Task<IActionResult> PlaceOrder([FromBody] CreateOrderModel  model)
        {
            try
            { 
                var status = await _requestClient.GetResponse<OrderConfirmed>(new OrderCreated { OrderId = orderId });
                if (status != null)
                {
                    return Ok(new { OrderId = orderId, Status = "Order confirmed" });
                }
                else
                {
                    return StatusCode(500, "Order processing failed.");
                }
            }
            catch (Exception e)
            {
                return StatusCode(504, "Timeout waiting for the order confirmation.");
            } 
        }
    }
    public class CreateOrderModel
    {
        public string OrderId { get; set; }
        public string CustomerName { get; set; }
        public double Amount { get; set; }
    }
}