Only the command line should be able to get credentials from the cache

src/AnimeClient/API/Kitsu/Auth.php

@@ -138,11 +138,16 @@ final class Auth {
 	 * @throws InvalidArgumentException
 	 */
 	public function getAuthToken(): ?string
+	{
+		if (PHP_SAPI === 'cli')
 		{
 			return $this->segment->get('auth_token', NULL)
 				?? $this->cache->get(K::AUTH_TOKEN_CACHE_KEY, NULL);
 		}
 
+		return $this->segment->get('auth_token', NULL);
+	}
+
 	/**
 	 * Retrieve the refresh token
 	 *
@@ -150,11 +155,16 @@ final class Auth {
 	 * @throws InvalidArgumentException
 	 */
 	private function getRefreshToken(): ?string
+	{
+		if (PHP_SAPI === 'cli')
 		{
 			return $this->segment->get('refresh_token')
 				?? $this->cache->get(K::AUTH_TOKEN_REFRESH_CACHE_KEY, NULL);
 		}
 
+		return $this->segment->get('refresh_token');
+	}
+
 	/**
 	 * Save the new authentication information
 	 *

src/AnimeClient/API/Kitsu/Model.php

@@ -155,19 +155,26 @@ final class Model {
 	 */
 	public function reAuthenticate(string $token)
 	{
-		$response = $this->getResponse('POST', K::AUTH_URL, [
+		$response = $this->requestBuilder->getResponse('POST', K::AUTH_URL, [
 			'headers' => [
+				'accept' => NULL,
+				'Content-type' => 'application/x-www-form-urlencoded',
 				'Accept-encoding' => '*'
-
 			],
 			'form_params' => [
 				'grant_type' => 'refresh_token',
 				'refresh_token' => $token
 			]
 		]);
-
 		$data = Json::decode(wait($response->getBody()->buffer()));
 
+		if (array_key_exists('error', $data))
+		{
+			dump($data['error']);
+			dump($response);
+			die();
+		}
+
 		if (array_key_exists('access_token', $data))
 		{
 			return $data;