diff --git a/app/controllers/my_courses.php b/app/controllers/my_courses.php
index c0dbeb3798a373aee5ec07d76a900954b1a78a91..6b1dae4dde91305e9fe326a51d441843fa6729e1 100644
--- a/app/controllers/my_courses.php
+++ b/app/controllers/my_courses.php
@@ -401,7 +401,10 @@ class MyCoursesController extends AuthenticatedController
 
         // Ensure last teacher cannot leave course
         $course = Course::find($course_id);
-        if ($course->members->findOneBy('user_id', $GLOBALS['user']->id)->status === 'dozent'
+        $teacher = $course->members->findOneBy('user_id', User::findCurrent()->id);
+        if (
+            $teacher
+            && $teacher->status === 'dozent'
             && count($course->getMembersWithStatus('dozent')) === 1
         ) {
             PageLayout::postError(sprintf(
diff --git a/lib/messaging.inc.php b/lib/messaging.inc.php
index b055c7f1a135b4e12312c930248cc572891c3402..22b7c25ec69393cb0e67dac26b5fef7b86ed4c19 100644
--- a/lib/messaging.inc.php
+++ b/lib/messaging.inc.php
@@ -161,7 +161,8 @@ class messaging
         $msg      = Message::find($message_id);
         $receiver = User::find($rec_user_id);
         $to       = $receiver->Email;
-
+        $reply_to = '';
+        $snd_fullname = '';
         // do not try to send mails to users without a mail address
         if (!$to) {
             return;