Sucuri has identified the cause of the outage, and they are working to get a fix pushed live as soon as possible. Traffic in the USA has been restored and only parts of Europe and Asia are still affected.
Sucuri is reporting connectivity issues impacting some Sucuri Firewall Clusters in parts of Europe and the USA. Their sysadmins are actively working on the issue, which they hope will be resolved shortly. We will continue to monitor the situation and provide updates. You can also track updates directly from Sucuri at http://status.sucuri.net/incidents/3128z75nygdk.