Date Calculation - Invalid Operation error

Hello, Could anyone please help me here. I need the calculation results has to show as particular a Date. Which specifies the Due date of the payment. (The formula which I have used is "Miro date(Date of invoice booked) + 30 (Credit Days what i 'm enjoying at present) - 2(Ahead of 2 days)).

But unfortunately the result of this evaluation look like- "#Invalid Operation".

Could anyone please guide what is this error and how can i overcome this.

Thanks in advance

Manuel

@Paul Newcome @Genevieve P - Good Day, Sorry to say that still, it's not working for me. I have already changed the Miro date column as the date type column. But Still the error is coming.

Hope you are clear with my question. (Suppose the Miro date is 03/05/2021. And I have 15 days credit. I would like pay before 2 days of my due date. So finally the due date has to show as - 16/05/2021. (03/05/2021+15-2). Will this work in smartsheet. Still I'm getting error- #Invalid coumn value.

Please advise.

You will also want to make sure that the column you are putting the formula into is a date type column.

@Paul Newcome - Thanks. It's worked.