fix link to sandbox (no https)
diff --git a/index.html b/index.html
index 74c6a0c..c7b5ed3 100644
--- a/index.html
+++ b/index.html
@@ -28,7 +28,6 @@
         <script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js"></script>
         <script src="https://oss.maxcdn.com/libs/respond.js/1.4.2/respond.min.js"></script>
         <![endif]-->
-
     </head>
 
     <body id="page-top" class="index">
@@ -132,7 +131,7 @@
                         <h3>Discover &amp; Test</h3>
                         <p>In order to help you test your LWM2M solutions quickly, the Leshan project provides a Lightweight M2M standalone server you can freely connect to for evaluation purposes.</p>
                         <div class="text-center button-links">
-                            <a href="//leshan.eclipse.org" target="_blank" class="btn btn-default btn-lg" role="button">
+                            <a href="http://leshan.eclipse.org" target="_blank" class="btn btn-default btn-lg" role="button">
                                 <i class="fa fa-server"></i> LWM2M sandbox
                             </a>
                         </div>