Migration - FOREIGN KEY constraint

Question

Hi, I working with Code First when I run the migration I get error.

 

Introducing FOREIGN KEY constraint 'FK_dbo.Users_dbo.Campaigns_CampaignID' on table 'Users' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.
Could not create constraint. See previous errors.

 

Please, I need help, I don't understand why this error happens. 

 

Thanks,

   public class Message
   {
       public int ID { get; set; }
       public string Content { get; set; }
       public string Timestamp { get; set; }

       public int UserID { get; set; }
       public virtual User User { get; set; }

       public int RoomID { get; set; }
       public virtual Room Room { get; set; }
   }

    public class Room
    {
        public int ID { get; set; }
        [MaxLength(200)]
        public string RoomKey { get; set; }
        [StringLength(30, MinimumLength = 3)]
        public string Name { get; set; }

        public int UserCreator { get; set; }
        public virtual User User { get; set; }

        public int CampaignID { get; set; }
        public virtual Campaign Campaign { get; set; }

        public virtual ICollection Messages { get; set; }
    }

public class Company
{
    public int ID { get; set; }
    [StringLength(30, MinimumLength = 3)]
    public string Name { get; set; }

    public virtual ICollection Campaigns { get; set; }
}

public class Campaign
{
    public int ID { get; set; }
    [StringLength(50, MinimumLength = 3)]
    public string Name { get; set; }

    public int CompanyID { get; set; }
    public virtual Company Company { get; set; }

    public virtual ICollection Users { get; set; }
    public virtual ICollection Rooms { get; set; }
}

public class City
{
    public int ID { get; set; }
    [StringLength(50, MinimumLength = 3)]
    public string Name { get; set; }

    public virtual ICollection Users { get; set; }
}

public class User
{
    public int ID { get; set; }
    [StringLength(50, MinimumLength = 3)]
    public string UserName { get; set; }
    public string Password { get; set; }
    [StringLength(50, MinimumLength = 3)]

    public int CityID { get; set; }
    public virtual City City { get; set; }

    public int CampaignID { get; set; }
    public virtual Campaign Campaign { get; set; }

    public int RoomID { get; set; }
    public virtual Room Room { get; set; }

    public bool Status { get; set; }
    public DateTime RegisterDate { get; set; }
    public int UserCreator { get; set; }
}