diff --git a/extlib/OAuth.php b/extlib/OAuth.php
index 2e9142ab65..019f97201f 100644
--- a/extlib/OAuth.php
+++ b/extlib/OAuth.php
@@ -261,7 +261,7 @@ public static function from_request($http_method=NULL, $http_url=NULL, $paramete
               ? 'http'
               : 'https';
     $http_url = ($http_url) ? $http_url : $scheme .
-                              '://' . $_SERVER['SERVER_NAME'] .
+                              '://' . $_SERVER['HTTP_HOST'] . //SERVER_NAME isn't always correct, should be HTTP_HOST
                               ':' .
                               $_SERVER['SERVER_PORT'] .
                               $_SERVER['REQUEST_URI'];