diff --git a/machines/hippocampus/servers/public/matrix/server.nix b/machines/hippocampus/servers/public/matrix/server.nix
index 4aa113f..641cd78 100644
--- a/machines/hippocampus/servers/public/matrix/server.nix
+++ b/machines/hippocampus/servers/public/matrix/server.nix
@@ -30,6 +30,9 @@
           client = "https://glia.club";
           server = "glia.club:443";
         };
+
+        # TODO: Configure more in detail/for safety:
+        url_preview_domain_contains_allowlist = ["*"];
       };
     };
   };