diff --git a/core/postfix/conf/main.cf b/core/postfix/conf/main.cf
index dfa31514..a35ca16c 100644
--- a/core/postfix/conf/main.cf
+++ b/core/postfix/conf/main.cf
@@ -31,6 +31,7 @@ mydestination =
 # Relayhost if any is configured
 relayhost = {{ RELAYHOST }}
 {% if RELAYUSER %}
+smtp_sasl_auth_enable = yes
 smtp_sasl_password_maps = lmdb:/etc/postfix/sasl_passwd
 smtp_sasl_security_options = noanonymous, noplaintext
 smtp_sasl_tls_security_options = noanonymous