As a follow-up, switching to a completely different ISP (I just created a new “throw away” e-mail account to see what was going on here) I was able to get the registration to be completed. Still, bitcoins.org is on some kind of e-mail blackhole list or at least the ISP that hosts the e-mail server for registration is on one of those lists.
Re: (context post by RHorning)
Participants: RHorning