There's a new urban myth among college students that says they can get a $1000 from the government just for filing a tax form. For most of them, they simply aren't eligible. A full time unmarried student, under age 24, even if you don't qualify as a dependent, is only eligible for the refundable portion of the American Opportunity Credit if he supports himself by working. You cannot be supporting yourself on parental support, 529 plans or student loans & grants. You usually must have actually paid tuition, not had it paid by scholarships & grants. It is usually best if the parent claims that credit.
You cannot claim a credit if you are, or can be, claimed as a dependent by someone else.
If you are eligible, you have answered something wrong, in the interview. But, a lot of people are just not eligible. See https://www.irs.gov/Individuals/AOTC
https://www.irs.gov/newsroom/american-opportunity-tax-credit-questions-and-answers
https://www.irs.gov/individuals/llc
https://www.irs.gov/pub/irs-pdf/f8917.pdf
