Error: Inserting 'Customer Call' record raised at least one error. Please review the errors.

I’m creating a new form and it requires selecting a business account. so I have written the Code as follows in the DAC,

 #region BAccountID
        [PXDBInt()]
        [PXDefault()]
        [PXUIField(DisplayName = "Business Account")]
        [PXSelector(typeof(Search<BAccount.bAccountID>),
            typeof(BAccount.acctCD),
            typeof(BAccount.acctName)
        )]

    public virtual int? BAccountID { get; set; }
    public abstract class bAccountID : PX.Data.BQL.BqlInt.Field<bAccountID> { }
    #endregion

when I’m entering the new record, it raised an error as follows,

 “Error: Inserting  'Customer Call' record raised at least one error. Please review the errors.” 

But when I’m selecting another business account in the same form, I can save the data successfully. However, I can't save the data with the business account I initially chose and it raised an error like “Error: Updating  'Customer Call' record raised at least one error. Please review the errors.”

how can I resolve this error? Does anyone have an idea?

Thank you!