If you are eligible, you have answered something wrong, in the interview. But, a lot of people are just not eligible. If you are eligible, you will have to file an amended return to claim it. Wait for your original return to be fully processed (you get your refund) before amending.
How to amend https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed
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. There is an exception, for the non refundable credit.
Reference: Line 7 instructions for form 8863. https://www.irs.gov/instructions/i8863
See Also see this TT FAQ https://ttlc.intuit.com/questions/3383321-why-didn-t-i-get-a-credit-or-deduction-for-education-expen...
https://www.irs.gov/Individuals/AOTC
https://www.irs.gov/newsroom/american-opportunity-tax-credit-questions-and-answers
https://www.irs.gov/credits-deductions/individuals/education-credits-questions-and-answers
https://www.irs.gov/individuals/llc
https://ttlc.intuit.com/community/college-education/discussion/i-have-a-1098-t-form-that-i-received-...
