diff --git a/configuration.nix b/configuration.nix
index f84babc..3e8d7eb 100644
--- a/configuration.nix
+++ b/configuration.nix
@@ -269,6 +269,7 @@
       security.LOGIN_REMEMBER_DAYS = 365;
       attachment.MAX_SIZE = 10;  # file upload size (MB)
       service.DEFAULT_ALLOW_CREATE_ORGANIZATION = false;
+      service.EMAIL_DOMAIN_BLOCKLIST = "gmail.com";
     };
   };