title: poste.io Let's encrypt certificate issue exception
body: <p>I am using the poste.io mail server.  While trying to issue the SSL cert using lets encrypt, it throws below error.  Anyone has observed it already and could fix it?</p>
  
  <pre><code>[2016-11-08 00:12:44] LEScript.INFO: Account already registered. Continuing.
  [2016-11-08 00:12:44] LEScript.INFO: Starting certificate generation process for domains
  [2016-11-08 00:12:44] LEScript.INFO: Requesting challenge for mail.domain.ltd
  [2016-11-08 00:12:45] LEScript.INFO: Sending signed request to /acme/new-authz
  [2016-11-08 00:12:45] LEScript.INFO: Got challenge token for mail.domain.ltd
  [2016-11-08 00:12:45] LEScript.INFO: Token for mail.domain.ltd saved at /opt/www//.well-known/acme-challenge/UEyhta88fiS_E5WTn-SOxKI-lqbsK1-eTOceiE_UnTQ and should be available at http://mail.domain.ltd/.well-known/acme-challenge/UEyhta88fiS_E5WTn-SOxKI-lqbsK1-eTOceiE_UnTQ
  [2016-11-08 00:12:47] LEScript.ERROR: Please check http://mail.domain.ltd/.well-known/acme-challenge/UEyhta88fiS_E5WTn-SOxKI-lqbsK1-eTOceiE_UnTQ - token not available
  [2016-11-08 00:12:47] LEScript.ERROR: #0 /opt/mailserver-admin/src/Analogic/LetsEncryptBundle/Handler/LeHandler.php(55): Analogic\ACME\Lescript-&gt;signDomains(Array)
  [2016-11-08 00:12:47] LEScript.ERROR: #1 /opt/mailserver-admin/src/Analogic/LetsEncryptBundle/Controller/LeController.php(74): Analogic\LetsEncryptBundle\Handler\LeHandler-&gt;renew(true)
  [2016-11-08 00:12:47] LEScript.ERROR: #2 [internal function]: Analogic\LetsEncryptBundle\Controller\LeController-&gt;issueAction(Object(Symfony\Component\HttpFoundation\Request))
  [2016-11-08 00:12:47] LEScript.ERROR: #3 /opt/mailserver-admin/var/bootstrap.php.cache(3040): call_user_func_array(Array, Array)
  [2016-11-08 00:12:47] LEScript.ERROR: #4 /opt/mailserver-admin/var/bootstrap.php.cache(2995): Symfony\Component\HttpKernel\HttpKernel-&gt;handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1)
  [2016-11-08 00:12:47] LEScript.ERROR: #5 /opt/mailserver-admin/var/bootstrap.php.cache(2335): Symfony\Component\HttpKernel\HttpKernel-&gt;handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
  [2016-11-08 00:12:47] LEScript.ERROR: #6 /opt/mailserver-admin/web/app.php(19): Symfony\Component\HttpKernel\Kernel-&gt;handle(Object(Symfony\Component\HttpFoundation\Request))
  [2016-11-08 00:12:47] LEScript.ERROR: #7 {main}
  </code></pre>
  
  <p>Have posted in <a href="https://bitbucket.org/analogic/mailserver/issues/139/lets-encrypt-certificate-issue-exception" rel="nofollow noreferrer">https://bitbucket.org/analogic/mailserver/issues/139/lets-encrypt-certificate-issue-exception</a> but seems they only respond to pro customers. :(</p>