diff --git a/services/monitoring/blackbox.nix b/services/monitoring/blackbox.nix
index bcc7308..cce4517 100644
--- a/services/monitoring/blackbox.nix
+++ b/services/monitoring/blackbox.nix
@@ -39,7 +39,22 @@ in
           http:
             fail_if_not_ssl: true
             preferred_ip_protocol: ip4
-            valid_status_codes: []  # Accept any status, we only care about TLS
+            valid_status_codes:
+              - 200
+              - 204
+              - 301
+              - 302
+              - 303
+              - 307
+              - 308
+              - 400
+              - 401
+              - 403
+              - 404
+              - 405
+              - 500
+              - 502
+              - 503
     '';
   };