diff --git a/details.php b/details.php
index 3ff8fb7..696958e 100644
--- a/details.php
+++ b/details.php
@@ -7,6 +7,7 @@ require_once($CFG->libdir . '/formslib.php');
 require_once($CFG->dirroot . '/user/selector/lib.php');
 require_once('classes/user_selector.php');
 require_once('classes/usergrades_form.php');
+require_once('vendor/autoload.php');
 
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
 use PhpOffice\PhpSpreadsheet\Writer\Xlsx;