diff --git a/sogo-mail/sogo-config-secret.yaml b/sogo-mail/sogo-config-secret.yaml
index 748cedc..fa87503 100644
--- a/sogo-mail/sogo-config-secret.yaml
+++ b/sogo-mail/sogo-config-secret.yaml
@@ -39,6 +39,7 @@ spec:
             displayName: "Shared Addresses"
             filter: "(objectClass=user)"
         SOGoIMAPServer: "imaps://stalwart.rubenhensen.nl:993"
+        SOGoMailingMechanism: "smtp"
         SOGoSMTPServer: "smtp://stalwart.rubenhensen.nl:587/?tls=YES&tlsVerifyMode=allowInsecureLocalhost"
         SOGoSMTPAuthenticationType: "PLAIN"
         NGImap4DisableIMAP4Pooling: "NO"