DNA test results

So I just received results of a DNA test, and it had a family tree, with 1,503 people I am related to. My mom and dad are both in my life. And I know a lot about my moms family, and not so much (if anything at all) about my dads side. I know to see people you’re related to, they must also take a test. BUT, everyone I saw I was related to was on my mom’s side.

I find it strange that not a single person out of 1,503 are on my dad’s side. I want to bring it up to him out of curiosity, but I am becoming a bit concerned about those results.

Just looking for guidance.