diff --git a/docs/configuration.rst b/docs/configuration.rst
index d6cb8357..1541a345 100644
--- a/docs/configuration.rst
+++ b/docs/configuration.rst
@@ -37,7 +37,7 @@ The ``POSTMASTER`` is the local part of the postmaster email address. It is
 recommended to setup a generic value and later configure a mail alias for that
 address.
 
-The ``WILDCARD_SENDERS`` setting is a comma delimited list of user email addresses that are allowed to send emails from any address (spoofing the sender).
+The ``WILDCARD_SENDERS`` setting is a comma delimited list of user email addresses that are allowed to send emails from any existing address (spoofing the sender).
 
 The ``AUTH_RATELIMIT`` holds a security setting for fighting attackers that
 try to guess user passwords. The value is the limit of failed authentication attempts