diff --git a/program/lib/Roundcube/rcube_imap_generic.php b/program/lib/Roundcube/rcube_imap_generic.php
index 9c3f0073af7..5a1f057918a 100644
--- a/program/lib/Roundcube/rcube_imap_generic.php
+++ b/program/lib/Roundcube/rcube_imap_generic.php
@@ -426,6 +426,7 @@ protected function closeSocket()
         if ($this->fp) {
             fclose($this->fp);
             $this->fp = null;
+            $this->cmd_num = 0;
         }
     }