title: Trouble with PayPal IPN Service. IPN Simulator not giving expected result
body: <p>I am trying to use the <a href="https://developer.paypal.com/webapps/developer/docs/classic/ipn/integration-guide/IPNIntro/" rel="nofollow noreferrer">PayPal IPN service</a>. I have set up my Notification URL (herein referred to as 'my page') to respond to the IPN and validate the request as instructed. In addition, my page sends me an email regardless of the status of the IPN. It appears to work as expected <em>unless</em> I test via the <a href="https://developer.paypal.com/webapps/developer/applications/ipn_simulator" rel="nofollow noreferrer">PayPal IPN Simulator</a>.</p>
  
  <p><strong>These are my findings. Does anyone have any idea what I am doing wrong and how I can get this to work as expected in the IPN simulator (case 3 and 4)?</strong> </p>
  
  <p><strong>Case 1)</strong> I go to my page in-browser (http <em>or</em> https) passing no params:</p>
  
  <blockquote>
    <p>Result = <strong>as expected</strong>: PayPal's IPN service responds 'INVALID' and my page sends me an email.</p>
  </blockquote>
  
  <p><strong>Case 2)</strong> I go to my page in-browser (http <em>or</em> https) and pass the sample params detailed in the <a href="https://developer.paypal.com/webapps/developer/docs/classic/ipn/integration-guide/IPNIntro/" rel="nofollow noreferrer">integration guide</a>:</p>
  
  <blockquote>
    <p>Result = <strong>as expected</strong>: PayPal's IPN service responds 'INVALID' and my page sends me an email of all the details.</p>
  </blockquote>
  
  <p><strong>Case 3)</strong> I use the <a href="https://developer.paypal.com/webapps/developer/applications/ipn_simulator" rel="nofollow noreferrer">PayPal IPN Simulator</a> and test my page over <em>insecure</em> protocol (http):</p>
  
  <blockquote>
    <p>Result = <strong>PARTIALLY as expected</strong>: The service says '<em>IPN sent successfully</em>'  but my page <strong>does not</strong> send me an email (suggesting it wasn't in fact called at all).<br />
    <strong>Expecting</strong>: '<em>IPN sent successfully</em>' and my page to send an email.</p>
  </blockquote>
  
  <p><strong>Case 4)</strong> I use the <a href="https://developer.paypal.com/webapps/developer/applications/ipn_simulator" rel="nofollow noreferrer">PayPal IPN Simulator</a> and test my page over a <em>secure</em> protocol (https):</p>
  
  <blockquote>
    <p>Result = <strong>NOT as expected</strong>: The service says '<em>We're sorry, we could not send an IPN</em>' and my page <strong>does not</strong> send me an email (suggesting no attempt was made or the URL wasn't reachable).<br />
    <strong>Expecting</strong>: '<em>IPN sent successfully</em>' and my page to send an email.</p>
  </blockquote>
  
  <p>I found <a href="https://stackoverflow.com/questions/20015292/why-doesnt-paypals-ipn-simulator-work-with-https-addresses">this related unanswered question</a> and <a href="https://stackoverflow.com/questions/17912563/error-testing-https-response-server-in-paypal-ipn-simulator">this q&amp;a</a> but nothing else useful. Any help would be much appreciated. Perhaps I'm missing something fundamental. I have to admit to struggling a little with the various API's and instructions. </p>