diff --git a/mastus/letsencrypt.nix b/mastus/letsencrypt.nix
index 38e3f1a..fe7ef22 100644
--- a/mastus/letsencrypt.nix
+++ b/mastus/letsencrypt.nix
@@ -5,7 +5,7 @@
     "gebner.org" = {
       webroot = "/var/lib/acme/acme-challenge";
       email = "gebner@gebner.org";
-      extraDomains = [
+      extraDomainNames = [
         "git.gebner.org"
         "mail.gebner.org"
         "gebner.org"