Api in .Net Core does not fetch information from a list

The problem is that when I have to fetch a general list of friends (unfiltered) Entity framework fetches the data properly but by adding the Include() method to fetch information associated with the object, the API is unable to show me the results on postman.

What I am trying to do is a list that is capable of adding the data of the user that sends a request and also of its receiver. I feel that it is very likely an error in the way of establishing relationships or how I am making such a query.

Thanks for any help you can give me.

Other posts I tried unsuccessfully:

  1. Entity Framework Code First - two Foreign Keys from same table
  2. Defining multiple Foreign Key for the Same table in Entity Framework Code First

Note: UserRequest is assumed to have two foreign keys that come from User (i.e. from the same table).

The classes I have are:

UserRequest's controller class:

public class UserRequestController : ControllerBase
{
     private readonly DataContext context;

     public UserRequestController(DataContext context)
     {
          this.context = context;
     }

     [HttpGet("GetRequestList")]
     public IEnumerable<UserRequest> GetRequestList()
     {
          // If I add the include () it doesn't show anything, 
          // If I leave it as it is here it loads everything except the associated objects
          var userRequest = context.UserRequests;
          return userRequest;
     }

User's class:

 public class User
 {
    public string Id{ get; set; }

    public string FirstName { get; set; }

    public string LastName { get; set; }

    public ICollection<UserRequest> UserSenders { get; set; }

    public ICollection<UserRequest> UserReceptors { get; set; }
}

UserRequest's class:

 public class UserRequest
 {
    public string Id{ get; set; }

    public string SenderId { get; set; }

    public User Sender { get; set; }

    public string ReceptorId { get; set; }

    public User Receptor { get; set; }

    public int Status { get; set; }
}

DataContext's class

public class DataContext : DbContext
{
     public DbSet<UserRequest> UserRequests { get; set; }

     public DataContext(DbContextOptions<DataContext> options) : base(options)
     {

     }

     protected override void OnModelCreating(ModelBuilder builder)
     {
          base.OnModelCreating(builder);

          builder.Entity<UserRequest>()
                 .HasOne(u => u.Sender)
                 .WithMany(uf => uf.UserSenders)
                 .HasForeignKey(uf => uf.SenderId)
                 .OnDelete(DeleteBehavior.Restrict);

          builder.Entity<UserRequest>()
                 .HasOne(u => u.Receptor)
                 .WithMany(uf => uf.UserReceptors)
                 .HasForeignKey(uf => uf.ReceptorId)
                 .OnDelete(DeleteBehavior.Restrict);
     }
}