diff --git a/code/Helper/S3.php b/code/Helper/S3.php
index 975bdfb..789f49b 100644
--- a/code/Helper/S3.php
+++ b/code/Helper/S3.php
@@ -20,7 +20,7 @@ public function generateSecureUrl($url) {
     }
 
     protected function _tryBucketSubdomain($url, $secret, $expires) {
-        preg_match_all("/^https?:\/\/(.*)\.s3[\w-]*\.amazonaws\.com\/(.*)$/", $url, $matches);
+        preg_match_all("/^https?:\/\/(.*)\.s3[\w.-]*\.amazonaws\.com\/(.*)$/", $url, $matches);
 
         if ($matches && count($matches) > 0 && count($matches[0]) > 0) {
             list($full_url, $bucket, $filename) = $matches;