diff --git a/mail-server/rspamd.nix b/mail-server/rspamd.nix
index 1d0136f..ee48b28 100644
--- a/mail-server/rspamd.nix
+++ b/mail-server/rspamd.nix
@@ -114,7 +114,9 @@ in
             path = "${cfg.dkimKeyDirectory}/$domain.$selector.key";
             selector = "${cfg.dkimSelector}";
             # Allow for usernames w/o domain part
-            allow_username_mismatch = true
+            allow_username_mismatch = true;
+            # Don't normalize DKIM key selection for subdomains
+            use_esld = false;
           '';
         };
         "dmarc.conf" = {