Since the recent filesystem fracas, the new accounts could not be created on nodus / dokuwiki (for the controls workshop, for example).
I started sendmail on nodus using the command: sudo /etc/init.d/sendmail start
sudo /etc/init.d/sendmail start
and the SwiftMail plugin on there is now sending out the confirmation emails again. This will happen each time we reboot nodus, so let's replace it.