diff --git a/dovecot.nix b/dovecot.nix
index 745bfa9..669aa7a 100644
--- a/dovecot.nix
+++ b/dovecot.nix
@@ -19,7 +19,7 @@ let
       ''
     }
 
-    disable_plaintext_auth = no
+    disable_plaintext_auth = yes
     auth_mechanisms = plain login
 
     userdb {