diff --git a/tide.nix b/tide.nix
index da5fd4e..80f5fdd 100644
--- a/tide.nix
+++ b/tide.nix
@@ -11,7 +11,7 @@
     # Reuse the wildcard cert already issued for *.${domainName}
     # in configuration.nix instead of requesting a new one per
     # subdomain.
-    nginx.useACMEHost = domainName;
+    nginx.useACMEHost = null;
   };
 
   # Don't fail evaluation when secrets/tide.yaml is missing (e.g.