The Student Who Never Listens

I've been teaching seventh grade math for six years now, and I pride myself on my ability to connect with students. Most kids come into my class at the start of the year and we build a rapport throughout the semester. But there's one student who has me stumped. His name is Mark, and he never listens to what I say in class. He's smart enough; his test scores are decent, but he doesn't do any of the homework or participate in class discussions. When I try to talk to him one-on-one about why he isn't engaging with the material, all he says is that 'math just isn't his thing.' It frustrates me because there could be underlying issues causing this behavior, and I want to help him succeed, but every attempt at conversation seems to fall flat. Is this kind of disconnect common in teaching? Should I keep trying to reach out to Mark, or am I better off focusing on the other students who are more responsive?