Apologies for the downtime which was at Invision's end.
"Downtime Incident
Early this morning, our launch configurations that have been in place for some time started failing. An internal utility at AWS that has been in place for years was no longer operating. A work around has been put in place and we are investigating with our AWS account representative as to the root cause of this failure. They do not yet know at this time. Our sincerest apologies for this downtime event. We have monitoring, automatic scaling, and various systems in place to prevent just such an issue. However, with such a low level piece of the AWS systems failing without warning, we were unable to quickly recover. At this time we have no further information but can promise we will work with AWS to determine root cause."