title: Enable USPS in Magento
body: <p>I'm trying to enable USPS in Magento. I already created an account for USPS and ask their staff to move it to production server.</p>
  
  <p>Then I fill up all necessary fields in System -> Configuration -> Shipping method -> USPS. I tried to search around and corrected all fields but I'm still unable to make it works.</p>
  
  <p>I have enabled debug in USPS module and catch below response from USPS (there's no error at all):</p>
  
  <pre><code>&lt;RateV4Response&gt;
  &lt;Package ID="0"&gt;
  &lt;ZipOrigination&gt;92672&lt;/ZipOrigination&gt;
  &lt;ZipDestination&gt;90503&lt;/ZipDestination&gt;
  &lt;Pounds&gt;0&lt;/Pounds&gt;
  &lt;Ounces&gt;0.2&lt;/Ounces&gt;
  &lt;Size&gt;REGULAR&lt;/Size&gt;
  &lt;Machinable&gt;TRUE&lt;/Machinable&gt;
  &lt;Zone&gt;1&lt;/Zone&gt;
  &lt;Postage CLASSID="3"&gt;
  &lt;MailService&gt;
  Priority Mail Express 1-Day&amp;lt;sup&amp;gt;&amp;#8482;&amp;lt;/sup&amp;gt;
  &lt;/MailService&gt;
  &lt;Rate&gt;14.10&lt;/Rate&gt;
  &lt;/Postage&gt;
  &lt;Postage CLASSID="2"&gt;
  &lt;MailService&gt;
  Priority Mail Express 1-Day&amp;lt;sup&amp;gt;&amp;#8482;&amp;lt;/sup&amp;gt; Hold For Pickup
  &lt;/MailService&gt;
  &lt;Rate&gt;14.10&lt;/Rate&gt;
  &lt;/Postage&gt;
  &lt;Postage CLASSID="55"&gt;
  &lt;MailService&gt;
  Priority Mail Express 1-Day&amp;lt;sup&amp;gt;&amp;#8482;&amp;lt;/sup&amp;gt; Flat Rate Boxes
  &lt;/MailService&gt;
  &lt;Rate&gt;39.95&lt;/Rate&gt;
  &lt;/Postage&gt;
  &lt;/Package&gt;
  &lt;/RateV4Response&gt;
  </code></pre>
  
  <p>It seems that I have received correct data, however in front-end, I still only see "This shipping method is currently unavailable...."</p>
  
  <p>Do you have any idea about this?</p>
  
  <p>Thanks!</p>