diff --git a/git_system.nix b/git_system.nix
index 34b1c3d..c017c57 100644
--- a/git_system.nix
+++ b/git_system.nix
@@ -59,6 +59,7 @@ in
         };
         mailer = {
           ENABLED = true;
+          PROTOCOL = "smtp";
           SMTP_ADDR = "80.151.91.109";
           SMTP_PORT = 25;
           FROM = "noreply@ptspaper.de";