diff --git a/local/o365/classes/feature/coursesync/main.php b/local/o365/classes/feature/coursesync/main.php
index 679a85e02..ea294e3ca 100644
--- a/local/o365/classes/feature/coursesync/main.php
+++ b/local/o365/classes/feature/coursesync/main.php
@@ -951,8 +951,8 @@ public function process_course_reset(stdClass $course, stdClass $o365object, boo
                     $resetgroupnameprefix = 'disconnected-';
                 }
                 $updatedmailnickname = $resetgroupnameprefix . utils::get_group_mail_alias($course);
-                if (strlen($updatedmailnickname) > 60) {
-                    $updatedmailnickname = substr($updatedmailnickname, 0, 60);
+                if (strlen($updatedmailnickname) > 59) {
+                    $updatedmailnickname = substr($updatedmailnickname, 0, 59);
                 }
                 $updatedexistinggroup = [
                     'id' => $existinggroup['id'],
diff --git a/local/o365/classes/feature/coursesync/utils.php b/local/o365/classes/feature/coursesync/utils.php
index 432e9f984..4cdc09259 100644
--- a/local/o365/classes/feature/coursesync/utils.php
+++ b/local/o365/classes/feature/coursesync/utils.php
@@ -368,7 +368,7 @@ public static function get_group_mail_alias(stdClass $course) : string {
 
         $coursepart = static::clean_up_group_mail_alias($coursepart);
 
-        $coursepartmaxlength = 60 - strlen($groupmailaliasprefix) - strlen($groupmailaliassuffix);
+        $coursepartmaxlength = 59 - strlen($groupmailaliasprefix) - strlen($groupmailaliassuffix);
         if (strlen($coursepart) > $coursepartmaxlength) {
             $coursepart = substr($coursepart, 0, $coursepartmaxlength);
         }