Conversion failed when converting the nvarchar value 'YES' to data type int

Hi Experts,

while executing the below query error showing.

"Conversion failed when converting the nvarchar value 'YES' to data type int"

SELECT T0.[DocEntry]
,T0.[DocNum]
,T0.[DocDate]
, T0.[CardCode]
, T0.[CardName]
,T0.[Comments]
, T0.[DocTotal]
, T0.[DocTotal] - T0.[VatSum] AS 'Sales Value'
, T0.[DocTotal] - T0.[VatSum] - T0.[GrosProfit] AS 'Purchase Costs'
,CASE
WHEN T0.[U_Airfrieght] IS NULL THEN 0
ELSE T0.[U_Airfrieght]
END AS 'Air frieght'
,CASE
WHEN T0.[U_InlandCharges] IS NULL THEN 0
ELSE T0.[U_InlandCharges]
END AS 'Inland Charges'
,CASE
WHEN T0.[U_Duty] IS NULL THEN 0
ELSE T0.[U_Duty]
END AS 'Duty'
, T0.[DocTotal] - T0.[VatSum] - T0.[GrosProfit] +
CASE
WHEN T0.[U_Airfrieght] IS NULL THEN 0
ELSE T0.[U_Airfrieght]
END
+ CASE
WHEN T0.[U_InlandCharges] IS NULL THEN 0
ELSE T0.[U_InlandCharges]
END
+ CASE
WHEN T0.[U_Duty] IS NULL THEN 0
ELSE T0.[U_Duty]
END
AS 'Total Costs'
, T0.[GrosProfit] -
CASE
WHEN T0.[U_Airfrieght] IS NULL THEN 0
ELSE T0.[U_Airfrieght]
END
- CASE
WHEN T0.[U_InlandCharges] IS NULL THEN 0
ELSE T0.[U_InlandCharges]
END
- CASE
WHEN T0.[U_Duty] IS NULL THEN 0
ELSE T0.[U_Duty]
END
AS 'Gross Profit'

FROM OINV T0 WHERE T0.[DocDate] between '10-01-2021' and '10-31-2021'