This incident holded on for some minutes. Text of the error message:
503 Backend fetch failed
Our servers are having problems at the moment. Please try again in a few minutes. There may be additional information on our Facebook and Twitter pages.
Please provide the details below if you report this error to the system administrators via https://phabricator.miraheze.org:
Error 503 Backend fetch failed, forwarded for 18.104.22.168, 127.0.0.1 (Varnish XID 1377520) via cp1 at Fri, 07 Jul 2017 08:49:25 GMT.