diff --git a/lib/grouplib.php b/lib/grouplib.php
index 4919ca42e73..ebd469ed1f5 100644
--- a/lib/grouplib.php
+++ b/lib/grouplib.php
@@ -433,7 +433,7 @@ function groups_print_activity_menu($cm, $urlroot, $return=false, $hideallpartic
 
     // Display error if urlroot is not absolute (this causes the non-JS version
     // to break)
-    if (strpos($urlroot, 'htxtp') !== 0) { // Will also work for https
+    if (strpos($urlroot, 'http') !== 0) { // Will also work for https
         debugging('groups_print_activity_menu requires absolute URL for ' .
             '$urlroot, not <tt>' . s($urlroot) . '</tt>. Example: ' .
             'groups_print_activity_menu($cm, $CFG->wwwroot . \'/mod/mymodule/view.php?id=13\');',