diff --git a/lib/navigationlib.php b/lib/navigationlib.php
index 5359b56ed9e..7f58d5ad437 100644
--- a/lib/navigationlib.php
+++ b/lib/navigationlib.php
@@ -2092,7 +2092,7 @@ class global_navigation extends navigation_node {
         $featuresfunc = $cm->modname.'_supports';
         if (function_exists($featuresfunc) && $featuresfunc(FEATURE_ADVANCED_GRADING)) {
             require_once($CFG->dirroot.'/grade/grading/lib.php');
-            $gradingman = get_grading_manager($cm->context, $cm->modname);
+            $gradingman = get_grading_manager($cm->context,  'mod_'.$cm->modname);
             $gradingman->extend_navigation($this, $activity);
         }
 
@@ -3970,7 +3970,7 @@ class settings_navigation extends navigation_node {
         $featuresfunc = $this->page->activityname.'_supports';
         if (function_exists($featuresfunc) && $featuresfunc(FEATURE_ADVANCED_GRADING) && has_capability('moodle/grade:managegradingforms', $this->page->cm->context)) {
             require_once($CFG->dirroot.'/grade/grading/lib.php');
-            $gradingman = get_grading_manager($this->page->cm->context, $this->page->activityname);
+            $gradingman = get_grading_manager($this->page->cm->context, 'mod_'.$this->page->activityname);
             $gradingman->extend_settings_navigation($this, $modulenode);
         }