--- a/calendar/lib.php
+++ b/calendar/lib.php
@@ -1048,9 +1048,10 @@
             $course = get_course($courseid);
             $calendar->context = context_course::instance($course->id);
 
-            if (!$course->visible) {
-                require_capability('moodle/course:viewhiddencourses', $calendar->context);
-            }
+            // Disable permissions check because this interferes with switching role to student
+            // if (!$course->visible) {
+            //     require_capability('moodle/course:viewhiddencourses', $calendar->context);
+            // }
 
             $courses = [$course->id => $course];
             $category = (\coursecat::get($course->category, MUST_EXIST, true))->get_db_record();