My T3 has an entry in Box 21 but nothing for Boxes 52 or 53. I kept getting an error message that Boxes 52 and 53 needed to be entered even though my T3 does not show these boxes. I finally entered the same amount in Box 53 from Box 21 and my Turbo Tax error message disappeared. I was able to Net File with no issues.
Hope this helps someone else.
