Connectivity has been restored.

This is the official explanation we received from AWS:

Between 09:45 and 13:18 UTC+2, we experienced increased 5xx errors for CloudFront customers utilizing VPC Origins connectivity. Our engineers were automatically engaged and immediately began investigating the root cause. By 11:57 UTC+2, we identified the root cause of the issue as an internal constraint on the fleet that manages connections to private VPC origins. When this constraint was reached, the system responsible for distributing routing configuration to our network processors failed to load the updated configuration data correctly, affecting routing of VPC Origin connections. At 12:52 UTC+2, we took multiple mitigation actions that led to to full recovery at 13:18 UTC+2. Now that the issue has been mitigated, customers who temporarily changed their origin type can safely revert these changes. Customers utilizing other origin types were not affected by this issue. The issue has been resolved and the service is operating normally.

The Commslab application is currently unavailable due to a service outage at Amazon Web Services, our hosting provider.

Starting at 12:45 AM PDT, we are experiencing increased 5xx errors for CloudFront customers utilizing VPC Origins connectivity.

See https://health.aws.amazon.com/health/status for updates from AWS themselves.

Please note that our Commslab API is unaffected, so end users of the app are not affected.