We are currently investigating some connections issues that are making our service inaccessible. Updates will be posted here as we know more.
Update: 01-Jun-2016 at 10:22 CEST: It looks like a DDoS attack. We are putting in place mitigation strategies and expect the situation to improve soon.
Update: 01-Jun-2016 at 10:50 CEST: We have put measures in place and services are working normally again.
Update: 01-Jun-2016 at 16:01 CEST: Further analysis of the situation has revealed the large spike in traffic that initially looked very much like a DDoS attack, was in fact a problem caused by an upstream Internet provider having a routing problem. The situation is resolved.