diff --git a/modules/nixos/security/acme/default.nix b/modules/nixos/security/acme/default.nix
index e8cd265..023a07f 100644
--- a/modules/nixos/security/acme/default.nix
+++ b/modules/nixos/security/acme/default.nix
@@ -64,10 +64,10 @@ in
         environmentFile = config.sops.templates."netcup.env".path;
       };
 
-      certs."${cfg.domainName}" = {
+      certs."${cfg.domainname}" = {
         server = mkIf cfg.staging "https://acme-staging-v02.api.letsencrypt.org/directory";
         dnsResolver = "1.1.1.1:53";
-        extraDomainNames = [ "*.${cfg.domainName}" ];
+        extraDomainNames = [ "*.${cfg.domainname}" ];
       };
     };