If you sold the property in 2017, then there's no way possible you "disposed" of it in 2016. Selling the property is but one possible way of disposing of it.
Did you convert the property back to personal use in 2016 maybe? Additionally, for the entire time you owned the property, was it classified as a rental for less than one year and did that classification***NOT*** cross tax years? (Both must be true to answer that last question with a yes.)
