diff --git a/src/Exception/BadResponseException.php b/src/Exception/BadResponseException.php
new file mode 100644
index 0000000..34da81a
--- /dev/null
+++ b/src/Exception/BadResponseException.php
@@ -0,0 +1,20 @@
+<?php
+
+/**
+ * This file is part of the ProxmoxVE PHP API wrapper library (unofficial).
+ *
+ * @copyright 2014 César Muñoz <zzantares@gmail.com>
+ * @license http://opensource.org/licenses/MIT The MIT License.
+ */
+
+namespace ProxmoxVE\Exception;
+
+/**
+ * BadResponseException class. Is the exception thrown when proxmox
+ * return status_code >= 400, thus the ProxmoxVE API client can not be used.
+ *
+ * @author César Muñoz <zzantares@gmail.com>
+ */
+class BadResponseException extends \RuntimeException
+{
+}
diff --git a/src/Proxmox.php b/src/Proxmox.php
index d192072..b04bf2f 100644
--- a/src/Proxmox.php
+++ b/src/Proxmox.php
@@ -14,6 +14,7 @@
 use GuzzleHttp\Psr7\Request;
 
 use ProxmoxVE\Exception\AuthenticationException;
+use ProxmoxVE\Exception\BadResponseException;
 
 /**
  * ProxmoxVE class. In order to interact with the proxmox server, the desired
@@ -154,6 +155,10 @@ private function processHttpResponse($response)
             return null;
         }
 
+        if ($response->getStatusCode() >= 400) {
+            throw new BadResponseException($response->getReasonPhrase());
+        }
+
         switch ($this->fakeType) {
             case 'pngb64':
                 $base64 = base64_encode($response->getBody());