I entered a 1098-T, but why have I not received an Education Tax Credit?

Can you be claimed as someone else's dependent?  Are you filing married filing separately?  Either of those would prevent you from getting an education credit.

https://www.irs.gov/help/ita/am-i-eligible-to-claim-an-education-credit

https://ttlc.intuit.com/questions/3383321-why-didn-t-i-get-a-credit-or-deduction-for-education-expenses

here'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.

Reference: Line 7 instructions for form 8863. https://www.irs.gov/instructions/i8863

If you are eligible, you have answered  something wrong, in the interview. But, a lot of people are just not eligible. 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-from-my-school-and-i-entered-all-the-information-but-it-said-i/01/998249#M23054