I’m having trouble saving the data..

Question

Problem when saving data "ex = {" An entity object can not be referenced by multiple instances of IEntityChangeTracker. "}

public class Transactions
{
[Key]
public long Id { get; set; }
public string Url { set; get; }
public bool? Showsender { get; set; }
public virtual PaymentStatus PaymentStatusItem { get; set; }
public string Trackingnumber { set; get; }
public DateTime? Executiondatetime { set; get; }
public virtual Account SourceAccount { set; get; }
public virtual Account DestinationAccount { set; get; }
public Decimal? Amount { set; get; }
public string Currency { set; get; }
public string Type { set; get; }
public string Status { set; get; }
public string Description { set; get; }
public decimal? CurrentBalance { get; set; }
public decimal? Balance { get; set; }
public virtual TransactionType TransactionTypeItem { get; set; }
public virtual Account DestinationAccountItem { get; set; }
public virtual Account SourceAccountItem { get; set; }
}
public bool Save(Transactions tran)
{
try
{
db.transactons.Add(tran);
db.SaveChanges();
return true;
}
catch (Exception ex)
{ } return false;
}

I tried but I couldn't find a solution to this problem, please help.