diff --git a/app/code/community/ProxiBlue/ReCaptcha/Model/Recaptcha.php b/app/code/community/ProxiBlue/ReCaptcha/Model/Recaptcha.php
index c24fcac..4358cf6 100644
--- a/app/code/community/ProxiBlue/ReCaptcha/Model/Recaptcha.php
+++ b/app/code/community/ProxiBlue/ReCaptcha/Model/Recaptcha.php
@@ -159,7 +159,9 @@ public function isCorrect($word)
     public function getUrl()
     {
         return
-            ProxiBlue_ReCaptcha_Helper_Data::RECAPTCHA_API_SERVER . ProxiBlue_ReCaptcha_Helper_Data::RECAPTCHA_API_PATH
+            ProxiBlue_ReCaptcha_Helper_Data::RECAPTCHA_API_SERVER 
+            . '/'
+            . ProxiBlue_ReCaptcha_Helper_Data::RECAPTCHA_API_PATH
             . '/challenge?k=' . $this->_public_key;
     }