diff --git a/src/Exception/OAuthServerException.php b/src/Exception/OAuthServerException.php
index b0309290..09ef4ec5 100644
--- a/src/Exception/OAuthServerException.php
+++ b/src/Exception/OAuthServerException.php
@@ -2,10 +2,10 @@
 
 namespace League\OAuth2\Server\Exception;
 
-use League\OAuth2\Server\Utils\RedirectUri;
 use Psr\Http\Message\ResponseInterface;
 use Zend\Diactoros\Response;
 use Zend\Diactoros\ServerRequest;
+use Zend\Diactoros\Uri;
 
 class OAuthServerException extends \Exception
 {
@@ -184,6 +184,7 @@ class OAuthServerException extends \Exception
     /**
      * Invalid refresh token
      *
+     * @param string|null $hint
      * @return static
      */
     public static function invalidRefreshToken($hint = null)
@@ -236,16 +237,21 @@ class OAuthServerException extends \Exception
         }
 
         if ($this->redirectUri !== null) {
-            $headers['Location'] = RedirectUri::make($this->redirectUri, $payload);
+            $redirectUri = new Uri($this->redirectUri);
+            parse_str($redirectUri->getQuery(), $redirectPayload);
+
+            $headers['Location'] = (string) $redirectUri->withQuery(http_build_query(
+                array_merge($redirectPayload, $payload)
+            ));
         }
 
         foreach ($headers as $header => $content) {
             $response = $response->withHeader($header, $content);
         }
 
-        $response = $response->withStatus($this->getHttpStatusCode());
         $response->getBody()->write(json_encode($payload));
-        return $response;
+
+        return $response->withStatus($this->getHttpStatusCode());
     }
 
     /**
diff --git a/src/Exception/UnauthorizedClientException.php b/src/Exception/UnauthorizedClientException.php
deleted file mode 100644
index fd1f18c3..00000000
--- a/src/Exception/UnauthorizedClientException.php
+++ /dev/null
@@ -1,36 +0,0 @@
-<?php
-/**
- * OAuth 2.0 Unauthorized Client Exception
- *
- * @package     league/oauth2-server
- * @author      Alex Bilbie <hello@alexbilbie.com>
- * @copyright   Copyright (c) Alex Bilbie
- * @license     http://mit-license.org/
- * @link        https://github.com/thephpleague/oauth2-server
- */
-
-namespace League\OAuth2\Server\Exception;
-
-/**
- * Exception class
- */
-class UnauthorizedClientException extends OAuthException
-{
-    /**
-     * {@inheritdoc}
-     */
-    public $httpStatusCode = 400;
-
-    /**
-     * {@inheritdoc}
-     */
-    public $errorType = 'unauthorized_client';
-
-    /**
-     * {@inheritdoc}
-     */
-    public function __construct()
-    {
-        parent::__construct('The client is not authorized to request an access token using this method.');
-    }
-}
diff --git a/src/Exception/UnsupportedResponseTypeException.php b/src/Exception/UnsupportedResponseTypeException.php
deleted file mode 100644
index 8707f0c5..00000000
--- a/src/Exception/UnsupportedResponseTypeException.php
+++ /dev/null
@@ -1,37 +0,0 @@
-<?php
-/**
- * OAuth 2.0 Unsupported Response Type Exception
- *
- * @package     league/oauth2-server
- * @author      Alex Bilbie <hello@alexbilbie.com>
- * @copyright   Copyright (c) Alex Bilbie
- * @license     http://mit-license.org/
- * @link        https://github.com/thephpleague/oauth2-server
- */
-
-namespace League\OAuth2\Server\Exception;
-
-/**
- * Exception class
- */
-class UnsupportedResponseTypeException extends OAuthException
-{
-    /**
-     * {@inheritdoc}
-     */
-    public $httpStatusCode = 400;
-
-    /**
-     * {@inheritdoc}
-     */
-    public $errorType = 'unsupported_response_type';
-
-    /**
-     * {@inheritdoc}
-     */
-    public function __construct($parameter, $redirectUri = null)
-    {
-        parent::__construct('The authorization server does not support obtaining an access token using this method.');
-        $this->redirectUri = $redirectUri;
-    }
-}
diff --git a/src/Grant/AbstractGrant.php b/src/Grant/AbstractGrant.php
index 490ecf4c..c6ffc760 100644
--- a/src/Grant/AbstractGrant.php
+++ b/src/Grant/AbstractGrant.php
@@ -80,6 +80,11 @@ abstract class AbstractGrant implements GrantTypeInterface
      */
     protected $pathToPublicKey;
 
+    /**
+     * @var \DateInterval
+     */
+    protected $refreshTokenTTL;
+
     /**
      * @param ClientRepositoryInterface $clientRepository
      */
@@ -128,6 +133,14 @@ abstract class AbstractGrant implements GrantTypeInterface
         $this->emitter = $emitter;
     }
 
+    /**
+     * @inheritdoc
+     */
+    public function setRefreshTokenTTL(\DateInterval $refreshTokenTTL)
+    {
+        $this->refreshTokenTTL = $refreshTokenTTL;
+    }
+
     /**
      * {@inheritdoc}
      */
@@ -291,7 +304,7 @@ abstract class AbstractGrant implements GrantTypeInterface
     {
         $refreshToken = new RefreshTokenEntity();
         $refreshToken->setIdentifier(SecureKey::generate());
-        $refreshToken->setExpiryDateTime((new \DateTime())->add(new \DateInterval('P1M')));
+        $refreshToken->setExpiryDateTime((new \DateTime())->add($this->refreshTokenTTL));
         $refreshToken->setAccessToken($accessToken);
 
         return $refreshToken;
diff --git a/src/Grant/ClientCredentialsGrant.php b/src/Grant/ClientCredentialsGrant.php
index 03c6c721..918586f9 100644
--- a/src/Grant/ClientCredentialsGrant.php
+++ b/src/Grant/ClientCredentialsGrant.php
@@ -32,14 +32,14 @@ class ClientCredentialsGrant extends AbstractGrant
     public function respondToRequest(
         ServerRequestInterface $request,
         ResponseTypeInterface $responseType,
-        \DateInterval $tokenTTL
+        \DateInterval $accessTokenTTL
     ) {
         // Validate request
         $client = $this->validateClient($request);
         $scopes = $this->validateScopes($request, $client);
 
         // Issue and persist access token
-        $accessToken = $this->issueAccessToken($tokenTTL, $client, $client->getIdentifier(), $scopes);
+        $accessToken = $this->issueAccessToken($accessTokenTTL, $client, $client->getIdentifier(), $scopes);
         $this->accessTokenRepository->persistNewAccessToken($accessToken);
 
         // Inject access token into response type
diff --git a/src/Grant/GrantTypeInterface.php b/src/Grant/GrantTypeInterface.php
index 5bc9bf08..a6a5c63a 100644
--- a/src/Grant/GrantTypeInterface.php
+++ b/src/Grant/GrantTypeInterface.php
@@ -11,7 +11,6 @@
 
 namespace League\OAuth2\Server\Grant;
 
-use DateInterval;
 use League\Event\EmitterInterface;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
 use League\OAuth2\Server\Repositories\ClientRepositoryInterface;
@@ -24,6 +23,13 @@ use Psr\Http\Message\ServerRequestInterface;
  */
 interface GrantTypeInterface
 {
+    /**
+     * Set refresh token TTL
+     *
+     * @param \DateInterval $refreshTokenTTL
+     */
+    public function setRefreshTokenTTL(\DateInterval $refreshTokenTTL);
+
     /**
      * Return the identifier
      *
@@ -43,14 +49,14 @@ interface GrantTypeInterface
      *
      * @param \Psr\Http\Message\ServerRequestInterface                  $request
      * @param \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface $responseType
-     * @param \DateInterval                                             $tokenTTL
+     * @param \DateInterval                                             $accessTokenTTL
      *
      * @return \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface
      */
     public function respondToRequest(
         ServerRequestInterface $request,
         ResponseTypeInterface $responseType,
-        DateInterval $tokenTTL
+        \DateInterval $accessTokenTTL
     );
 
     /**
diff --git a/src/Grant/PasswordGrant.php b/src/Grant/PasswordGrant.php
index 50593ef3..9f4f41e8 100644
--- a/src/Grant/PasswordGrant.php
+++ b/src/Grant/PasswordGrant.php
@@ -51,6 +51,8 @@ class PasswordGrant extends AbstractGrant
     ) {
         $this->userRepository = $userRepository;
         $this->refreshTokenRepository = $refreshTokenRepository;
+
+        $this->refreshTokenTTL = new \DateInterval('P1M');
     }
 
     /**
@@ -59,7 +61,7 @@ class PasswordGrant extends AbstractGrant
     public function respondToRequest(
         ServerRequestInterface $request,
         ResponseTypeInterface $responseType,
-        \DateInterval $tokenTTL
+        \DateInterval $accessTokenTTL
     ) {
         // Validate request
         $client = $this->validateClient($request);
@@ -67,7 +69,7 @@ class PasswordGrant extends AbstractGrant
         $scopes = $this->validateScopes($request, $client);
 
         // Issue and persist new tokens
-        $accessToken = $this->issueAccessToken($tokenTTL, $client, $user->getIdentifier(), $scopes);
+        $accessToken = $this->issueAccessToken($accessTokenTTL, $client, $user->getIdentifier(), $scopes);
         $refreshToken = $this->issueRefreshToken($accessToken);
         $this->accessTokenRepository->persistNewAccessToken($accessToken);
         $this->refreshTokenRepository->persistNewRefreshToken($refreshToken);
diff --git a/src/Grant/RefreshTokenGrant.php b/src/Grant/RefreshTokenGrant.php
index d8348d25..cf3286c8 100644
--- a/src/Grant/RefreshTokenGrant.php
+++ b/src/Grant/RefreshTokenGrant.php
@@ -42,6 +42,8 @@ class RefreshTokenGrant extends AbstractGrant
         RefreshTokenRepositoryInterface $refreshTokenRepository
     ) {
         $this->refreshTokenRepository = $refreshTokenRepository;
+
+        $this->refreshTokenTTL = new \DateInterval('P1M');
     }
 
     /**
@@ -50,8 +52,9 @@ class RefreshTokenGrant extends AbstractGrant
     public function respondToRequest(
         ServerRequestInterface $request,
         ResponseTypeInterface $responseType,
-        \DateInterval $tokenTTL
+        \DateInterval $accessTokenTTL
     ) {
+        // Validate request
         $client          = $this->validateClient($request);
         $oldRefreshToken = $this->validateOldRefreshToken($request, $client->getIdentifier());
         $scopes          = $this->validateScopes($request, $client);
@@ -75,9 +78,9 @@ class RefreshTokenGrant extends AbstractGrant
         $this->accessTokenRepository->revokeAccessToken($oldRefreshToken['access_token_id']);
         $this->refreshTokenRepository->revokeRefreshToken($oldRefreshToken['refresh_token_id']);
 
-        $accessToken = $this->issueAccessToken($tokenTTL, $client, $oldRefreshToken['user_id'], $scopes);
+        // Issue and persist new tokens
+        $accessToken = $this->issueAccessToken($accessTokenTTL, $client, $oldRefreshToken['user_id'], $scopes);
         $refreshToken = $this->issueRefreshToken($accessToken);
-
         $this->accessTokenRepository->persistNewAccessToken($accessToken);
         $this->refreshTokenRepository->persistNewRefreshToken($refreshToken);
 
diff --git a/src/Middleware/AuthenticationServerMiddleware.php b/src/Middleware/AuthenticationServerMiddleware.php
index 28bd39cb..14ac1c32 100644
--- a/src/Middleware/AuthenticationServerMiddleware.php
+++ b/src/Middleware/AuthenticationServerMiddleware.php
@@ -34,11 +34,13 @@ class AuthenticationServerMiddleware
     public function __invoke(ServerRequestInterface $request, ResponseInterface $response, callable $next)
     {
         try {
-            $response = $server->respondToRequest($request, $response);
+            $response = $this->server->respondToRequest($request, $response);
         } catch (OAuthServerException $exception) {
             return $exception->generateHttpResponse($response);
         } catch (\Exception $exception) {
-            return $response->withStatus(500)->write($exception->getMessage());
+            $response->getBody()->write($exception->getMessage());
+
+            return $response->withStatus(500);
         }
 
         if (in_array($response->getStatusCode(), [400, 401, 500])) {
diff --git a/src/Middleware/ResourceServerMiddleware.php b/src/Middleware/ResourceServerMiddleware.php
index 874a14c6..1794cdce 100644
--- a/src/Middleware/ResourceServerMiddleware.php
+++ b/src/Middleware/ResourceServerMiddleware.php
@@ -33,18 +33,14 @@ class ResourceServerMiddleware
      */
     public function __invoke(ServerRequestInterface $request, ResponseInterface $response, callable $next)
     {
-        if ($request->hasHeader('authorization') === false) {
-            $exception = OAuthServerException::accessDenied('Missing authorization header');
-
+        try {
+            $request = $this->server->getResponseType()->determineAccessTokenInHeader($request);
+        } catch (OAuthServerException $exception) {
             return $exception->generateHttpResponse($response);
-        }
+        } catch (\Exception $exception) {
+            $response->getBody()->write($exception->getMessage());
 
-        $request = $this->server->getResponseType()->determineAccessTokenInHeader($request);
-
-        if ($request->getAttribute('oauth_access_token') === null) {
-            $exception = OAuthServerException::accessDenied($request->getAttribute('oauth_access_token_error'));
-
-            return $exception->generateHttpResponse($response);
+            return $response->withStatus(500);
         }
 
         // Pass the request and response on to the next responder in the chain
diff --git a/src/ResponseTypes/AbstractResponseType.php b/src/ResponseTypes/AbstractResponseType.php
index 2388582f..9605a463 100644
--- a/src/ResponseTypes/AbstractResponseType.php
+++ b/src/ResponseTypes/AbstractResponseType.php
@@ -13,7 +13,9 @@ namespace League\OAuth2\Server\ResponseTypes;
 
 use League\OAuth2\Server\Entities\Interfaces\AccessTokenEntityInterface;
 use League\OAuth2\Server\Entities\Interfaces\RefreshTokenEntityInterface;
+use League\OAuth2\Server\Exception\OAuthServerException;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
+use Psr\Http\Message\ServerRequestInterface;
 
 abstract class AbstractResponseType implements ResponseTypeInterface
 {
@@ -66,10 +68,22 @@ abstract class AbstractResponseType implements ResponseTypeInterface
     }
 
     /**
-     * @param \League\OAuth2\Server\Entities\Interfaces\RefreshTokenEntityInterface $refreshToken
+     * {@inheritdoc}
      */
     public function setRefreshToken(RefreshTokenEntityInterface $refreshToken)
     {
         $this->refreshToken = $refreshToken;
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function determineAccessTokenInHeader(ServerRequestInterface $request)
+    {
+        if ($request->hasHeader('authorization') === false) {
+            throw OAuthServerException::accessDenied('Missing "Authorization" header');
+        }
+
+        return $request;
+    }
 }
diff --git a/src/ResponseTypes/BearerTokenResponse.php b/src/ResponseTypes/BearerTokenResponse.php
index 278b166d..c67bc990 100644
--- a/src/ResponseTypes/BearerTokenResponse.php
+++ b/src/ResponseTypes/BearerTokenResponse.php
@@ -16,10 +16,10 @@ use Lcobucci\JWT\Parser;
 use Lcobucci\JWT\Signer\Key;
 use Lcobucci\JWT\Signer\Rsa\Sha256;
 use League\OAuth2\Server\Entities\Interfaces\RefreshTokenEntityInterface;
+use League\OAuth2\Server\Exception\OAuthServerException;
 use League\OAuth2\Server\Utils\KeyCrypt;
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;
-use Zend\Diactoros\Response;
 
 class BearerTokenResponse extends AbstractResponseType
 {
@@ -78,6 +78,8 @@ class BearerTokenResponse extends AbstractResponseType
      */
     public function determineAccessTokenInHeader(ServerRequestInterface $request)
     {
+        $request = parent::determineAccessTokenInHeader($request);
+
         $header = $request->getHeader('authorization');
         $jwt = trim(preg_replace('/^(?:\s+)?Bearer\s/', '', $header[0]));
 
@@ -85,12 +87,12 @@ class BearerTokenResponse extends AbstractResponseType
             // Attempt to parse and validate the JWT
             $token = (new Parser())->parse($jwt);
             if ($token->verify(new Sha256(), $this->pathToPublicKey) === false) {
-                return $request->withAttribute('oauth_access_token_error', 'Access token could not be verified');
+                throw OAuthServerException::accessDenied('Access token could not be verified');
             }
 
             // Check if token has been revoked
             if ($this->accessTokenRepository->isAccessTokenRevoked($token->getClaim('jti'))) {
-                return $request->withAttribute('oauth_access_token_error', 'Access token has been revoked');
+                throw OAuthServerException::accessDenied('Access token has been revoked');
             }
 
             // Return the request with additional attributes
@@ -98,9 +100,9 @@ class BearerTokenResponse extends AbstractResponseType
                 ->withAttribute('oauth_client_id', $token->getClaim('aud'))
                 ->withAttribute('oauth_user_id', $token->getClaim('sub'))
                 ->withAttribute('oauth_scopes', $token->getClaim('scopes'));
-        } catch (\InvalidArgumentException $e) {
+        } catch (\InvalidArgumentException $exception) {
             // JWT couldn't be parsed so return the request as is
-            return $request->withAttribute('oauth_access_token_error', $e->getMessage());
+            throw OAuthServerException::accessDenied($exception->getMessage());
         }
     }
 }
diff --git a/src/Server.php b/src/Server.php
index a62e8b32..cc7eb320 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -26,11 +26,6 @@ class Server implements EmitterAwareInterface
      */
     protected $enabledGrantTypes = [];
 
-    /**
-     * @var ResponseTypeInterface[]
-     */
-    protected $grantResponseTypes = [];
-
     /**
      * @var DateInterval[]
      */
@@ -92,47 +87,23 @@ class Server implements EmitterAwareInterface
         $this->responseType = $responseType;
     }
 
-    /**
-     * Get the token type that grants will return in the HTTP response
-     *
-     * @return ResponseTypeInterface
-     */
-    public function getResponseType()
-    {
-        if (!$this->responseType instanceof ResponseTypeInterface) {
-            $this->responseType = new BearerTokenResponse(
-                $this->privateKeyPath,
-                $this->publicKeyPath,
-                $this->accessTokenRepository
-            );
-        }
-
-        return $this->responseType;
-    }
-
     /**
      * Enable a grant type on the server
      *
      * @param \League\OAuth2\Server\Grant\GrantTypeInterface $grantType
      * @param DateInterval                                   $accessTokenTTL
      */
-    public function enableGrantType(
-        GrantTypeInterface $grantType,
-        \DateInterval $accessTokenTTL
-    ) {
+    public function enableGrantType(GrantTypeInterface $grantType, \DateInterval $accessTokenTTL)
+    {
         $grantType->setAccessTokenRepository($this->accessTokenRepository);
         $grantType->setClientRepository($this->clientRepository);
         $grantType->setScopeRepository($this->scopeRepository);
         $grantType->setPathToPrivateKey($this->privateKeyPath);
         $grantType->setPathToPublicKey($this->publicKeyPath);
-
         $grantType->setEmitter($this->getEmitter());
+
         $this->enabledGrantTypes[$grantType->getIdentifier()] = $grantType;
 
-        // Set grant response type
-        $this->grantResponseTypes[$grantType->getIdentifier()] = $this->getResponseType();
-
-        // Set grant access token TTL
         $this->grantTypeAccessTokenTTL[$grantType->getIdentifier()] = $accessTokenTTL;
     }
 
@@ -160,7 +131,7 @@ class Server implements EmitterAwareInterface
             if ($grantType->canRespondToRequest($request)) {
                 $tokenResponse = $grantType->respondToRequest(
                     $request,
-                    $this->grantResponseTypes[$grantType->getIdentifier()],
+                    $this->getResponseType(),
                     $this->grantTypeAccessTokenTTL[$grantType->getIdentifier()]
                 );
             }
@@ -172,4 +143,22 @@ class Server implements EmitterAwareInterface
 
         return $tokenResponse->generateHttpResponse($response);
     }
+
+    /**
+     * Get the token type that grants will return in the HTTP response
+     *
+     * @return ResponseTypeInterface
+     */
+    public function getResponseType()
+    {
+        if (!$this->responseType instanceof ResponseTypeInterface) {
+            $this->responseType = new BearerTokenResponse(
+                $this->privateKeyPath,
+                $this->publicKeyPath,
+                $this->accessTokenRepository
+            );
+        }
+
+        return $this->responseType;
+    }
 }
diff --git a/src/Utils/RedirectUri.php b/src/Utils/RedirectUri.php
deleted file mode 100644
index d00f29cc..00000000
--- a/src/Utils/RedirectUri.php
+++ /dev/null
@@ -1,34 +0,0 @@
-<?php
-/**
- * OAuth 2.0 Redirect URI generator
- *
- * @package     league/oauth2-server
- * @author      Alex Bilbie <hello@alexbilbie.com>
- * @copyright   Copyright (c) Alex Bilbie
- * @license     http://mit-license.org/
- * @link        https://github.com/thephpleague/oauth2-server
- */
-
-namespace League\OAuth2\Server\Utils;
-
-/**
- * RedirectUri class
- */
-class RedirectUri
-{
-    /**
-     * Generate a new redirect uri
-     *
-     * @param string $uri            The base URI
-     * @param array  $params         The query string parameters
-     * @param string $queryDelimiter The query string delimiter (default: "?")
-     *
-     * @return string The updated URI
-     */
-    public static function make($uri, $params = [], $queryDelimiter = '?')
-    {
-        $uri .= (strstr($uri, $queryDelimiter) === false) ? $queryDelimiter : '&';
-
-        return $uri . http_build_query($params);
-    }
-}