InvalidArgumentException: URI must be a string or UriInterface in Guzzle : <p>I get a guzzle error as above , when i am sending the following code from a drupal 8 site:</p>

<pre><code> $url="https://mywebsite.com/index.php";
 $client = \Drupal::httpClient();
 $client-&gt;setDefaultOption( array('verify' ,false));
 $post_data = $form_state-&gt;cleanValues()-&gt;getValues();

 $request = $client-&gt;post($url, $post_data);
</code></pre>
