If he is 24 or older , he can't be a dependent if he earns over $4050 even if he is a student.
If he is 23 or less (as of 12/31/16) then he can be a dependent and you are in the wrong part of the interview. You need to say he lives with you all year (if he is away at school he counts as living with you). Try deleting him as a dependent and then add him back with the correct "lives with" info. Also double check his age and birthdate.
