This is a bad time for Wikidata Query Service. We had a few issues
last week to update WDQS and reload all data. During this data reload,
we are running on a single server. And now this server is starting to
I honestly do not know yet what is happening except that we see a lot
of file (pipes actually) left open and that WDQS stops responding.
Investigation is going on  and we'll let you know what we find.
Sorry for the inconvenience and thank you all for your patience!
Operations Engineer, Discovery