diff --git a/src/AuthorizationServer.php b/src/AuthorizationServer.php
index 50407072..568574d7 100644
--- a/src/AuthorizationServer.php
+++ b/src/AuthorizationServer.php
@@ -73,141 +73,6 @@ class AuthorizationServer extends AbstractServer
      */
     protected $requireStateParam = false;
 
-    /**
-     * Exception error codes
-     * @var array
-     */
-    protected static $exceptionCodes = [
-        0   =>  'invalid_request',
-        1   =>  'unauthorized_client',
-        2   =>  'access_denied',
-        3   =>  'unsupported_response_type',
-        4   =>  'invalid_scope',
-        5   =>  'server_error',
-        6   =>  'temporarily_unavailable',
-        7   =>  'unsupported_grant_type',
-        8   =>  'invalid_client',
-        9   =>  'invalid_grant'
-    ];
-
-    /**
-     * Exception error messages
-     * @var array
-     */
-    protected static $exceptionMessages = [
-        'invalid_request'           =>  'The request is missing a required parameter, includes an invalid parameter value, includes a parameter more than once, or is otherwise malformed. Check the "%s" parameter.',
-        'unauthorized_client'       =>  'The client is not authorized to request an access token using this method.',
-        'access_denied'             =>  'The resource owner or authorization server denied the request.',
-        'unsupported_response_type' =>  'The authorization server does not support obtaining an access token using this method.',
-        'invalid_scope'             =>  'The requested scope is invalid, unknown, or malformed. Check the "%s" scope.',
-        'server_error'              =>  'The authorization server encountered an unexpected condition which prevented it from fulfilling the request.',
-        'temporarily_unavailable'   =>  'The authorization server is currently unable to handle the request due to a temporary overloading or maintenance of the server.',
-        'unsupported_grant_type'    =>  'The authorization grant type "%s" is not supported by the authorization server',
-        'invalid_client'            =>  'Client authentication failed',
-        'invalid_grant'             =>  'The provided authorization grant is invalid, expired, revoked, does not match the redirection URI used in the authorization request, or was issued to another client. Check the "%s" parameter.',
-        'invalid_credentials'       =>  'The user credentials were incorrect.',
-        'invalid_refresh'           =>  'The refresh token is invalid.',
-    ];
-
-    /**
-     * Exception error HTTP status codes
-     * @var array
-     * RFC 6749, section 4.1.2.1.:
-     * No 503 status code for 'temporarily_unavailable', because
-     * "a 503 Service Unavailable HTTP status code cannot be
-     * returned to the client via an HTTP redirect"
-     */
-    protected static $exceptionHttpStatusCodes = [
-        'invalid_request'           =>  400,
-        'unauthorized_client'       =>  400,
-        'access_denied'             =>  401,
-        'unsupported_response_type' =>  400,
-        'invalid_scope'             =>  400,
-        'server_error'              =>  500,
-        'temporarily_unavailable'   =>  400,
-        'unsupported_grant_type'    =>  501,
-        'invalid_client'            =>  401,
-        'invalid_grant'             =>  400,
-        'invalid_credentials'       =>  400,
-        'invalid_refresh'           =>  400,
-    ];
-
-    /**
-     * Get all headers that have to be send with the error response
-     * @param  string $error The error message key
-     * @return array         Array with header values
-     */
-    public static function getExceptionHttpHeaders($error)
-    {
-        $headers = [];
-        switch (self::$exceptionHttpStatusCodes[$error]) {
-            case 401:
-                $headers[] = 'HTTP/1.1 401 Unauthorized';
-                break;
-            case 500:
-                $headers[] = 'HTTP/1.1 500 Internal Server Error';
-                break;
-            case 501:
-                $headers[] = 'HTTP/1.1 501 Not Implemented';
-                break;
-            case 400:
-            default:
-                $headers[] = 'HTTP/1.1 400 Bad Request';
-        }
-
-        // Add "WWW-Authenticate" header
-        //
-        // RFC 6749, section 5.2.:
-        // "If the client attempted to authenticate via the 'Authorization'
-        // request header field, the authorization server MUST
-        // respond with an HTTP 401 (Unauthorized) status code and
-        // include the "WWW-Authenticate" response header field
-        // matching the authentication scheme used by the client.
-        // @codeCoverageIgnoreStart
-        if ($error === 'invalid_client') {
-            $authScheme = null;
-            $request = new Request();
-            if ($request->server('PHP_AUTH_USER') !== null) {
-                $authScheme = 'Basic';
-            } else {
-                $authHeader = $request->header('Authorization');
-                if ($authHeader !== null) {
-                    if (strpos($authHeader, 'Bearer') === 0) {
-                        $authScheme = 'Bearer';
-                    } elseif (strpos($authHeader, 'Basic') === 0) {
-                        $authScheme = 'Basic';
-                    }
-                }
-            }
-            if ($authScheme !== null) {
-                $headers[] = 'WWW-Authenticate: '.$authScheme.' realm=""';
-            }
-        }
-        // @codeCoverageIgnoreEnd
-
-        return $headers;
-    }
-
-    /**
-     * Get an exception message
-     * @param  string $error The error message key
-     * @return string        The error message
-     */
-    public static function getExceptionMessage($error = '')
-    {
-        return self::$exceptionMessages[$error];
-    }
-
-    /**
-     * Get an exception code
-     * @param  integer $code The exception code
-     * @return string        The exception code type
-     */
-    public static function getExceptionType($code = 0)
-    {
-        return self::$exceptionCodes[$code];
-    }
-
     /**
      * Create a new OAuth2 authorization server
      * @return self