diff --git a/smtp.php b/smtp.php
index af09740..c24b88a 100644
--- a/smtp.php
+++ b/smtp.php
@@ -225,6 +225,8 @@ class smtp
     if (substr ($line, 0, 1) !== "2" && substr ($line, 0, 1) !== "3")
     {
       $this->debug ("Can't send mail : server answer : $line\n");
+      $this->putLine ("QUIT\r\n");
+      fclose ($this->smtpStream);
       throw new \Exception ("Can't send mail : server answer : $line", 500);
     }
     return $content;