--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -2947,17 +2947,18 @@ nsDocShell::DisplayLoadError(nsresult aE
         rv = NS_OK;
         formatStrCount = 1;
         error.AssignLiteral("fileNotFound");
     }
     else if (NS_ERROR_UNKNOWN_HOST == aError) {
         NS_ENSURE_ARG_POINTER(aURI);
         // Get the host
         nsCAutoString host;
-        aURI->GetHost(host);
+        nsCOMPtr<nsIURI> innermostURI = NS_GetInnermostURI(aURI);
+        innermostURI->GetHost(host);
         CopyUTF8toUTF16(host, formatStrs[0]);
         formatStrCount = 1;
         error.AssignLiteral("dnsNotFound");
     }
     else if(NS_ERROR_CONNECTION_REFUSED == aError) {
         NS_ENSURE_ARG_POINTER(aURI);
         // Build up the host:port string.
         nsCAutoString hostport;