title: No permission to use Datastream error mesage (Royal Mail Shipping API)
body: <p>I am using the Royal Mail Shipping API to 'Create a Shipment Request' &amp; to create 'Printed Labels'.</p>
  
  <p>The Printed Labels requests can be done a number of ways, I want to get this printed label in a PNG format which is easily done using the API by passing 'PNG' as a parameter. However for some reason I get the following error when I var_dump the response errors:</p>
  
  <pre><code>[errorCode] =&gt; E1184
  [errorDescription] =&gt; No permission to use Datastream
  </code></pre>
  
  <p>My code is as follows: -</p>
  
  <pre><code>public function PrintLabel($shipmentNumber, $order_tracking_id, $outputFormat = 'PDF')
  {
      $time = gmdate('Y-m-d\TH:i:s');
      $request = array(
              'integrationHeader' =&gt; array(
                  'dateTime' =&gt; $time,
                  'version' =&gt; '2',
                  'identification' =&gt; array(
                      'applicationId' =&gt; $this-&gt;api_application_id,
                      'transactionId' =&gt; $order_tracking_id
                  )
              ),
              'shipmentNumber' =&gt; $shipmentNumber,
              'outputFormat' =&gt; $outputFormat, // PDF, DS, DSPDF, PNG, DSPNG
      );
  
      $type = 'printLabel';
  
      $response = $this-&gt;makeRequest($type, $request);
      return $response-&gt;label;
  
  } // ef
  
  
  $rm = new RoyalMailLabelRequest();
  $response = $rm-&gt;PrintLabel('TTT000358756GB', '276831601444829801', 'PNG');
  echo $response;
  </code></pre>
  
  <p>Can anyone suggest why I am getting this 'no permission to use datastream error'?</p>