Register: Repaired.
My brother received this e-mail this morning:
Dear John, I am sorry for the inconveniences you face, however, I was not able to reproduce the mentioned issue from my end. I have successfully registered new “ewrewr” user and received following email… (etc. etc.)
Surely enough all the test e-mails that failed to go through yesterday have magically gone through today, meaning all is working now and people can register if they wish.
The internet will forever be a mystery to me.
<3 DarkSlinky.