JsonFormatter ReferenceLoopHandling

I have been struggling with this for a few days now, not finding any joy in any solutions I have found so far.

The project is built using Entity Framework 6 and WebAPI 2. I have changed the my WebApiConfig settings to

        config.Formatters.Remove(GlobalConfiguration.Configuration.Formatters.XmlFormatter);
        config.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;

There seems to be an infinite loop happening now with a System Out Of Memory Exception being thrown.

I cant seem to find the correct way to do this.

I have tried this within the WebAPI Method too, still the same symptom.

    public async Task<IHttpActionResult> GetCustomer_Title(int id)
    {
        Customer_Title c = await db.Customer_Title.FindAsync(id);
        if (c == null)
        {
            return NotFound();
        }

        var json = JsonConvert.SerializeObject(c, new JsonSerializerSettings()
        {
            ReferenceLoopHandling = ReferenceLoopHandling.Ignore
        });


        return Ok(json);
    }

and in my Customer_Title Class

 public partial class Customer_Title
    {

        public Customer_Title()
        {
            Customer = new HashSet<Customer>();
        }

        [Key]
        public int TitleID { get; set; }

        [Required]
        [StringLength(100)]
        public string TitleDescription { get; set; }

        public int InstanceID { get; set; }

        [JsonIgnore]
        public virtual ICollection<Customer> Customer { get; set; }

        public virtual System_Instance System_Instance { get; set; }
    }

The [JsonIgnore] Attribute seems to be doing nothing.