Education tax credit

I keep getting told that I am not eligible for an education tax credit but I know that I am. I'm in my second year of graduate school and had no problems getting a Lifetime Learning Credit through turbotax last year, but even though nothing has changed since last year I'm suddenly being told I am not eligible? I even went through the IRS website and did a questionnaire thing that told me I am eligible. Is there something I can do to fix this? For reference, I am single, I paid for my education through student loans, I am not claimed as a dependent by someone else, tuition and fees are $39,760, my income was only $5,903 due to being a full time graduate student but I also received around $20,000 in refunds from my student loans to cover expenses. Could there be something I am doing wrong or something about me that is causing me to not qualify?