diff --git a/machines/pretalx/configuration.nix b/machines/pretalx/configuration.nix
index 6ef5c8c..59f39d9 100644
--- a/machines/pretalx/configuration.nix
+++ b/machines/pretalx/configuration.nix
@@ -85,8 +85,8 @@ in
         user = "malobot@systemli.org";
         host = "mail.systemli.org";
         port = "465";
-        ssl = false;
-        tls = true;
+        ssl = true;
+        tls = false;
       };
 
     };