diff --git a/h5p.classes.php b/h5p.classes.php
index f9655a3..93c4213 100644
--- a/h5p.classes.php
+++ b/h5p.classes.php
@@ -2470,7 +2470,7 @@ class H5PCore {
     // Determine remote/visitor origin
     if ($type === 'network' ||
         ($type === 'local' && !preg_match('/^localhost$|^127(?:\.[0-9]+){0,2}\.[0-9]+$|^(?:0*\:)*?:?0*1$/i', $_SERVER['REMOTE_ADDR']))) {
-      if (filter_var($_SERVER['REMOTE_ADDR'], FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE)) {
+      if (isset($_SERVER['REMOTE_ADDR']) && filter_var($_SERVER['REMOTE_ADDR'], FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE)) {
         // Internet
         $this->h5pF->setOption('site_type', 'internet');
       }