diff --git a/nixos/modules/services/misc/forgejo.nix b/nixos/modules/services/misc/forgejo.nix
index ceee3e080eb5..fc5b371a1dc5 100644
--- a/nixos/modules/services/misc/forgejo.nix
+++ b/nixos/modules/services/misc/forgejo.nix
@@ -340,7 +340,7 @@ in
             };
             mailer = {
               ENABLED = true;
-              MAILER_TYPE = "sendmail";
+              PROTOCOL = "sendmail";
               FROM = "do-not-reply@example.org";
               SENDMAIL_PATH = "''${pkgs.system-sendmail}/bin/sendmail";
             };