You don't need to enter Box 20. Box 20 on the T4A(P) is automatically calculated by adding up the amounts in boxes 14 to 19.

I am ready to file, but I keep getting an error message on this page as I want to stop contributing to CPP as I turned 70 during the year, but have self-employed income.  No matter what I say on this page it won't allow me to proceed to file.  ANy suggestions?

In order to help you with this situation, we believe your best option is to contact our telephone support team for further assistance, as they have the option to view your screen to help you. To contact them, please follow this link: Contact Us. 

​​​​​​​Thank you for choosing TurboTax.