diff --git a/README.md b/README.md
index 6c78c62..0626867 100644
--- a/README.md
+++ b/README.md
@@ -89,7 +89,6 @@ It's not recommended, but it's possible to add NTLM-Authentication without valid
 | Name | type | default | description |
 |------|------|---------|-------------|
 | `badrequest` | `function` | `function(request, response, next) { response.sendStatus(400); }` | Function to handle HTTP 400 Bad Request. |
-| `internalservererror` | `function` | `function(request, response, next) { response.sendStatus(500); }` | Function to handle HTTP 500 Internal Server Error. |
 | `forbidden` | `function` | `function(request, response, next) { response.sendStatus(403); }` | Function to handle HTTP 403 Forbidden. |
 | `unauthorized` | `function` | `function(request, response, next) { response.statusCode = 401; response.setHeader('WWW-Authenticate', 'NTLM'); response.end();  }` | Function to handle HTTP 401 Unauthorized. |
 | `prefix` | `string` | `[express-ntlm]` | The prefix is the first argument passed to the `debug`-function. |
diff --git a/lib/express-ntlm.js b/lib/express-ntlm.js
index c25c6b4..08fb2f5 100644
--- a/lib/express-ntlm.js
+++ b/lib/express-ntlm.js
@@ -26,9 +26,6 @@ module.exports = function(options) {
         badrequest: function(request, response, next) {
             response.sendStatus(400);
         },
-        internalservererror: function(request, response, next) {
-            response.sendStatus(500);
-        },
         forbidden: function(request, response, next) {
             response.sendStatus(403);
         },
@@ -237,7 +234,7 @@ module.exports = function(options) {
             return handle_type1(request, response, next, ah_data[1], function(error) {
                 if (error) {
                     options.debug(options.prefix, error.stack);
-                    return options.internalservererror(request, response, next);
+                    return options.unauthorized(request, response, next);
                 }
             });
         }
@@ -247,12 +244,12 @@ module.exports = function(options) {
                 return handle_type3(request, response, next, ah_data[1], function(error) {
                     if (error) {
                         options.debug(options.prefix, error.stack);
-                        return options.internalservererror(request, response, next);
+                        return options.unauthorized(request, response, next);
                     }
                 });
             }
             options.debug(options.prefix, 'Unexpected NTLM message Type 3 in new connection for URI ' + request.protocol + '://' + request.get('host') + request.originalUrl);
-            return options.internalservererror(request, response, next);
+            return options.unauthorized(request, response, next);
         }
         options.debug(options.prefix, 'Type 2 message in client request');
         return options.badrequest(request, response, next);