At 12:02 the fiber line to Frankfurt failed, the traffic that is processed via Frankfurt was therefore automatically rerouted after a short interruption.
The reason for the outage is a power failure in the Interxion/Digital Realty FRA2 data center in Frankfurt. Other carriers are also affected by this, see for example the following status message: https://status.core-backbone.com/index.php?id=5081
Traffic is currently being routed transparently via Amsterdam and will be automatically rerouted as soon as everything is stable again.