Hmm, no, even after I forwarded the ports, restart the router, then no matter if I try my own registered name or the pre-generated one it gives me, after I select my display name and it says stuff like "Getting user record", at the "Getting regions" screen it errors out in 1-10 seconds.
EDIT: The fact that sometimes it takes 10 seconds for it to error "Couldn't connect to server", and sometimes it's quick, like 1-2 seconds makes me think the server is actually responding to me, rather than the request timing out. If it was timing out, it would always take the same length of time.
On the other hand, Dreamcast Now at that point is showing that I'm playing the game, so the server to some extent acknowledged my requests, at least to a degree.