Display correct error message when the client fails to establish P2P connection.

remoting/webapp/_locales/en/messages.json

Index: remoting/webapp/_locales/en/messages.json
diff --git a/remoting/webapp/_locales/en/messages.json b/remoting/webapp/_locales/en/messages.json
index e4104c356e81ffb28f558874889d444becea3f47..0a5c6db14e188ead75a0d917d48db8ed196219ee 100644
--- a/remoting/webapp/_locales/en/messages.json
+++ b/remoting/webapp/_locales/en/messages.json
@@ -111,6 +111,10 @@
     "message": "The access code is invalid. Please try again.",
     "description": "Error displayed if an invalid access code is entered."
   },
+  "ERROR_NETWORK_FAILURE": {
+    "message": "Unable to reach the host. This is probably due to the configuration of the network you are using.",
+    "description": "Error displayed when the host is online, but we are unable to connect to it due to network configuration."
+  },
   "ERROR_MISSING_PLUGIN": {
     "message": "Some components required for Chromoting are missing. Please make sure you're running the latest version of Chromium and try again.",
     "description": "Error displayed if the client plugin fails to load."