diff --git a/services/mailserver.nix b/services/mailserver.nix
index e71caa8..8e6c73d 100644
--- a/services/mailserver.nix
+++ b/services/mailserver.nix
@@ -26,5 +26,6 @@
     # Use Let's Encrypt certificates. Note that this needs to set up a stripped
     # down nginx and opens port 80.
     certificateScheme = "acme-nginx";
+    certificateDomains = [ "mail.spoodythe.one" ];
   };
 }