Second Life login services failure

At approximately 8:55AM all login services for the 1.18.6 series of Second Life viewers (release candidate and first look) failed for approximately 40 minutes. There are no signs of the disruption being specifically load-related, and regular release viewers were able to log in normally (if a little slowly) during the affected period.

Even though the problem has just been resolved, there is no word from Linden Lab acknowledging the outage or giving any insight into the matter.