Here's the appropriate error: the Let's Encrypt validation server can't reach your Apache webserver on port 80. Nor can I by the way. You need to make sure your webserver is reachable on port 80 from the world wide web.
Also, I don't really understand why you tried certbot --nginx --dry-run too? Do you have a nginx webserver running too perhaps? Although that's unlikely looking at the error message provided after you tried that..