The IRS will go by the 1098-T. But, there are circumstances where box 1 (bx 1 and/or box 2 for years prior to 2018) are blank or zero, but the taxpayer still paid for qualified expenses**. If this is the case, you need to provide the IRS with proof of payment (usually the school's invoices).
**The most common situation is that the spring 2018 term (for example) was billed in 2017 and shows on the 2017 1098-T; but you actually made the payment in 2018. You can claim the American Opportunity Credit on your 2018 tax return.
