So how did the prospective buyer even find your e-mail address...?
If I were you I would configure my web server so that it will only accept HTTP connections for hostnames that are your own. If you had done that then the buyer would probably never have found you.
The Whois record showed the title of my page which has my name lol. They contacted me in LinkedIn using that. Directed them to use the GoDaddy contact thing based on Whois. EDIT: I got it mixed up, they just browsed unstoppable.com which was not filtered out by my server.
And yeah I should have had server_name in my nginx config in the first place. This time I did some fun with multiple roots/domains on one server: one for unstoppable.com and the other for my actual website.
If I were you I would configure my web server so that it will only accept HTTP connections for hostnames that are your own. If you had done that then the buyer would probably never have found you.