diff --git a/public_html/index.php b/public_html/index.php
--- a/public_html/index.php
+++ b/public_html/index.php
@@ -150,7 +150,13 @@
 }

 // register some plugins
-$server->addPlugin(new \Sabre\DAV\Auth\Plugin($auth_backend, 'KolabDAV'));
+$realm='KolabDAV';
+$u=urldecode($_SERVER['REQUEST_URI']);
+preg_match('/[^\/]+@[^\/]+/', $u, $found);
+if (count($found) > 0) {
+  $realm=$realm.' '.$found[0];
+}
+$server->addPlugin(new \Sabre\DAV\Auth\Plugin($auth_backend, $realm));
 $server->addPlugin(new \Sabre\DAVACL\Plugin());

 if ($services['CALDAV']) {