If my income is less than $55,000 and my student tuition was $20,000 in 2020 and I don't owe any taxes, why am I not getting the full $2,000 lifetime learning credit back

[MinhT1]

The Lifetime Learning credit is a non-refundable credit. Therefore, if your tax liability of less than $2,000, you will not be able to use the full credit.

Please read this IRS document for more information.

[Hal_Al]

The Lifetime Leaning Credit (LLC) is non-refundable. It can only be used to offset your tax liability.  Once you tax is reduce to 0, non of the "left over" LLC is sent to you.  It is simply lost.