We are currently investigating some connection problems. It seems they may be related to a Distributed Denial of Service Attack. We will post further updates as they become available.
Update 28-May-2016 19:09 CEST: A DDoS attack is confirmed and action has been taken to mitigate the effects. We will continue to monitor the situation.
Update 29-May-2016 00:32 CEST: The effects of the DDoS attack have been mitigated and services are working normally. Marking this issue resolved.