diff --git a/reference/configuration/monolog.rst b/reference/configuration/monolog.rst
index 8acf1f5fbb1..ccd557712cd 100644
--- a/reference/configuration/monolog.rst
+++ b/reference/configuration/monolog.rst
@@ -52,6 +52,7 @@ Monolog Configuration Reference
                     from_email:           ~
                     to_email:             ~
                     subject:              ~
+                    mailer:               ~
                     email_prototype:
                         id:                   ~ # Required (when the email_prototype is used)
                         factory-method:       ~