diff --git a/web/README.md b/web/README.md
index 3bedcbb..a912ba6 100644
--- a/web/README.md
+++ b/web/README.md
@@ -56,10 +56,10 @@ change them unless you know what you want.
 - `SMTP_HOST_PASSWORD`: Default is an empty string.
 
 - `SMTP_USE_TLS`: Specifies wheather the SMTP connection is encrypted
-  via TLS. Default is `False`.
+  via TLS. Default is `False`. (`EMAIL_USE_TLS`/`EMAIL_USE_SSL` are mutually exclusive, so only set one of those settings.)
 
 - `SMTP_USE_SSL`: Specifies wheather the SMTP connection is encrypted
-  via SSL. Default is `False`.
+  via SSL. Default is `False`. (EMAIL_USE_TLS/EMAIL_USE_SSL are mutually exclusive, so only set one of those settings.)
 
 - `DJANGO_LOG_URL`: Path to the django's log file. Defaults to
   `/opt/mailman-web-data/logs/mailmanweb.log`.