Ous Son is in post schooling and we are not receiving any tax credits of any kind?

Our son is in his last year of law school. He is 24 years old. When I went to file our taxes, Turbo tax will not give us the Lifetime Learning Credit nor do we get any dependent credit? Nothing has changed since last year and we did receive these tax breaks. I cannot for the life of me figure out why Turbo Tax will not let us claim him this year? We actually pay his rent for his apartment at school and his tuition, books, etc... He does work and he filed his own taxes but checked that we could claim him as a dependent. What am I doing wrong?