diff --git a/lib/worker.js b/lib/worker.js
index a3520f2..97c0a7d 100644
--- a/lib/worker.js
+++ b/lib/worker.js
@@ -212,7 +212,7 @@ module.exports.create = function (webserver, xconfx, state) {
 
             if (!/^api\.[a-z0-9\-]+/.test(hostname)) {
               res.send({ error:
-               { message: "API access is restricted to proper 'api'-prefixed lowercase subdomains."
+               { message: "['" + hostname + "'] API access is restricted to proper 'api'-prefixed lowercase subdomains."
                    + " The HTTP 'Host' header must exist and must begin with 'api.' as in 'api.example.com'."
                    + " For development you may test with api.localhost.daplie.me (or any domain by modifying your /etc/hosts)"
                , code: 'E_NOT_API'