diff --git a/Client.php b/Client.php
index b7a1b28..250343c 100644
--- a/Client.php
+++ b/Client.php
@@ -21,7 +21,7 @@
 class Client extends \yii\base\Object {
 
 	/**
-	 * @var string API endpoint (default production)
+	 * @var string API url endpoint
 	 */
 	public $endpoint = '';
 
@@ -174,7 +174,7 @@ public function getData(
 	}
 
 	/**
-	 * Update with entity url
+	 * Put data with entity url
 	 *
 	 * @param string $entity_url
 	 * @param string $context view or edit
@@ -182,7 +182,7 @@ public function getData(
 	 *
 	 * @return self
 	 */
-	public function updateData(
+	public function putData(
 		$entity_url,
 		$context = 'edit',
 		array $data
@@ -203,7 +203,7 @@ public function updateData(
 	}
 
 	/**
-	 * Update with entity url
+	 * Patch with entity url
 	 *
 	 * @param string $entity_url
 	 * @param string $context view or edit
@@ -232,7 +232,7 @@ public function patchData(
 	}
 
 	/**
-	 * Add data with entity url
+	 * Post data with entity url
 	 *
 	 * @param string $entity_url
 	 * @param string $context view or edit
@@ -240,7 +240,7 @@ public function patchData(
 	 *
 	 * @return self
 	 */
-	public function addData(
+	public function postData(
 		$entity_url,
 		$context = 'view',
 		array $data
@@ -373,19 +373,23 @@ protected function executeRequest() {
 
 				// Check for response status code
 				if ( ! $this->response->isOk ) {
+					$result_content = Json::decode( $this->response->content, false );
 					switch ( $this->response->statusCode ) {
 						case 304:
 							throw new Exception(
 								'Not Modified.'
 							);
 						case 400:
+							$parameter_errors = [];
+							foreach($result_content->data->params as $param_error) {
+								$parameter_errors[] = $param_error;
+							}
 							throw new Exception(
-								'Bad Request: request ' . $this->request->getFullUrl() . ' was invalid.',
+								'Bad Request: '.implode(' | ', $parameter_errors).' (request ' . $this->request->getFullUrl() . ').',
 								Exception::FAIL
 							);
 						case 401:
-							// Handle {"code":"json_oauth1_nonce_already_used","message":"Invalid nonce - nonce has already been used","data":{"status":401}}
-							$result_content = Json::decode( $this->response->content, false );
+							// Nonce used can be retried, other 401 can not
 							if ( isset( $result_content->code ) && $result_content->code == 'json_oauth1_nonce_already_used' ) {
 								throw new Exception(
 									( isset( $result_content->message ) ? $result_content->message : $this->response->content ) .
@@ -394,7 +398,7 @@ protected function executeRequest() {
 								);
 							} else {
 								throw new Exception(
-									'Unauthorized: user does not have permission to access ' . $this->request->getFullUrl(),
+									'Unauthorized: '.$result_content->message.' (request ' . $this->request->getFullUrl() . ').',
 									Exception::FAIL
 								);
 							}
diff --git a/OAuth1.php b/OAuth1.php
index e7d50de..78c917b 100644
--- a/OAuth1.php
+++ b/OAuth1.php
@@ -59,18 +59,10 @@ class OAuth1 extends \yii\authclient\OAuth1
 	public $accessTokenMethod = 'POST';
 
 	/**
-	 * var $apiBaseUrl is Wordpress site url
+	 * var $apiBaseUrl is Wordpress site url (json slug is auto added)
 	 */
 	public $apiBaseUrl;
 
-	/**
-	 * @var array list of extra parameters, which should be used, while requesting user attributes from Wordpress API.
-	 *
-	 * @see http://oauth1.wp-api.org/docs/basics/Auth-Flow.html
-	 * @since 2.0.6
-	 */
-	public $attributeParams = [];
-
 	/**
 	 * @inheritdoc
 	 */
@@ -82,8 +74,8 @@ public function __construct( array $config ) {
 		$this->requestTokenUrl = $this->apiBaseUrl.'/'.$this->requestTokenUrl;
 		$this->accessTokenUrl = $this->apiBaseUrl.'/'.$this->accessTokenUrl;
 
-		// Set apiBaseUrl to Wordpress v2 URL
-		$this->apiBaseUrl = $this->apiBaseUrl.'/wp-json/wp/v2';
+		// Set apiBaseUrl to Wordpress Rest API base slug
+		$this->apiBaseUrl = $this->apiBaseUrl.'/wp-json';
 	}
 
 	/**