It seems that you incorrectly entered the code 2 or code 7 Form 1099-R with the IRA/SEP/SIMPLE box marked. Make sure that when entering this Form 1099-R that you indicate that you moved the money to another retirement account, that you did a combination of rolling over, converting and cashing out, then indicate that amount converted to Roth.
(If the Form 1099-R provided by the payer does not have the IRA/SEP/SIMPLE box marked, the transaction is not reportable on Form 8606. Such a transaction would instead be properly described as a taxable rollover from the traditional account in an employer's qualified retirement plan, not a Roth conversion.)
