diff --git a/src/Grant/AuthCodeGrant.php b/src/Grant/AuthCodeGrant.php
index 18720f45..d7900581 100644
--- a/src/Grant/AuthCodeGrant.php
+++ b/src/Grant/AuthCodeGrant.php
@@ -240,18 +240,19 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
                 $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
                 throw OAuthServerException::invalidClient();
             }
-        } elseif (is_array($client->getRedirectUri()) && count($client->getRedirectUri()) !== 1
-            || empty($client->getRedirectUri())
-        ) {
+	} elseif (is_array($client->getRedirectUri()) && count($client->getRedirectUri()) !== 1
+	    || empty($client->getRedirectUri())) {
             $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
             throw OAuthServerException::invalidClient();
+        } else {
+            $redirectUri = is_array($client->getRedirectUri())
+                ? $client->getRedirectUri()[0]
+                : $client->getRedirectUri();
         }
 
         $scopes = $this->validateScopes(
             $this->getQueryStringParameter('scope', $request, $this->defaultScope),
-            is_array($client->getRedirectUri())
-                ? $client->getRedirectUri()[0]
-                : $client->getRedirectUri()
+            $redirectUri
         );
 
         $stateParameter = $this->getQueryStringParameter('state', $request);
diff --git a/src/Grant/ImplicitGrant.php b/src/Grant/ImplicitGrant.php
index f3c9e694..5a6fccb1 100644
--- a/src/Grant/ImplicitGrant.php
+++ b/src/Grant/ImplicitGrant.php
@@ -149,18 +149,19 @@ class ImplicitGrant extends AbstractAuthorizeGrant
                 $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
                 throw OAuthServerException::invalidClient();
             }
-        } elseif (is_array($client->getRedirectUri()) && count($client->getRedirectUri()) !== 1
-            || empty($client->getRedirectUri())
-        ) {
+	} elseif (is_array($client->getRedirectUri()) && count($client->getRedirectUri()) !== 1
+            || empty($client->getRedirectUri())) {
             $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
             throw OAuthServerException::invalidClient();
+        } else {
+            $redirectUri = is_array($client->getRedirectUri())
+                ? $client->getRedirectUri()[0]
+                : $client->getRedirectUri();
         }
 
         $scopes = $this->validateScopes(
             $this->getQueryStringParameter('scope', $request, $this->defaultScope),
-            is_array($client->getRedirectUri())
-                ? $client->getRedirectUri()[0]
-                : $client->getRedirectUri()
+            $redirectUri
         );
 
         // Finalize the requested scopes