diff --git a/lib/servers.js b/lib/servers.js
index 5c351ee..1c2b7a1 100644
--- a/lib/servers.js
+++ b/lib/servers.js
@@ -59,12 +59,12 @@ module.exports.create = function (challenge) {
         var server = https.createServer(httpsOptions, servers.httpResponder);
 
         servers._servers.push(server);
-        servers.listen(port, function () {
+        server.listen(port, function () {
           if (opts.debug) {
             console.info('Listening https on', this.address());
           }
         });
-        servers.on('error', function (err) {
+        server.on('error', function (err) {
           if ('EADDRINUSE' === err.code) {
             console.error("");
             console.error("You already have a different server running on port '" + port + "'.");