Issue fully resolved.
Service is restored to full capacity.
The outage of the faulty front-end server has been resolved by our service provider. We are checking its health and restoring service.
Since 12h45 today our monitoring services detected an outage of one of our front-end servers. We are actively working on restoring capacity and will continue to monitor the situation. The services are up but unstable at times due to the load on the remaining capacity.