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 ...