Got a 503 trying to access https://phabricator.wikimedia.org/T121555#1881832 , not reproducible:
If you report this error to the Wikimedia System Administrators, please include the details below.
Request from 10.20.0.121 via cp1056 cp1056 ([10.64.32.133]:3128), Varnish XID 1493389825
Forwarded for: ww.xxx.yyy.zz, 10.20.0.122, 10.20.0.122, 10.20.0.121
Error: 503, Service Unavailable at Wed, 16 Dec 2015 12:43:28 GMT