Are you living in the SEO past?
Search engine optimization best practices are constantly changing, so if you haven't kept up with the changes you might be using old tactics.
Tech Radar said, "In layman’s terms, black hat SEO consists of website optimization strategies that are now deemed as unacceptable or unethical to search engines."
Examples include hidden text, cloaking, and keyword stuffing.
If you're still doing any of these things it's time to step it up!