Problem solved. I play around with the number of Box5 in 1098-T and this time the education credit changed. To claim education credit, the number in Box5 - part of amount in Box5 which is used for room and board < amount in Box1.
Just for someone have the same problem, if the education credit not claimed and you think it should, try restart the TurboTax or run maximize the return. It did not work for me initially after following Kris's suggestion.
Thanks KrisD15, excellent advice!
Have a wonderful day!
