I made that kind of mistake often early on in my sales career. The product I sold had a specific use in a specific field by specific disciplines, and was required by law in certain regions.
I always felt like such a dick when I'd get to the purchasing agent, make my hurried nervous pitch because I'm so excited to get through to someone and they'd (often kindly) explain that they literally never have any use case for my product.
After a few of those, I became more aware of how to prune my "leads" (read: list of phone numbers) to make sure I was only reaching out to people who could even use the dang thing and inserted a few exploratory questions into the opening salvo to double check.
I'm glad I don't have to do this via email, though. At least with the phone, I can hear tone and get quick, definite answers instead of just waiting on a reply.