One user is having issues connecting to Zimbra and receives a 503 error message from nginx. Checking the nginx log file I see
2010/02/17 08:32:15 [error] 12677#0: *3663 zmauth: route handler did not send server or port, client:, server:, request: "GET / HTTP/1.1", host: ""
If a colleague or myself connect to we can login just fine and we are on the same network as the troubled user. All DNS lookups respond okay. Any pointers please as this has me baffled.