I second that.<br><br>Verzonden vanaf mijn Sony Xperia™-smartphone<br><br>---- Maarten schreef ----<br><br>I&#39;m using letsencrypt certificates with roundcube and I&#39;m not having any<br>issues.<br><br><br>On 03/01/2018 07:49 PM, ɹןʇnqן wrote:<br>&gt; On Mar 1, 2018, at 09:21, NederHost/Sebastiaan Hoogeveen &lt;<a href="mailto:s.hoogeveen@nederhost.nl">s.hoogeveen@nederhost.nl</a>&gt; wrote:<br>&gt;&gt; The &#39;SSL alert number 48&#39; indicates that the server certificate cannot be verified due to being issued by an unknown CA. This is probably caused by a missing, outdated or improperly configured CA bundle on the machine running Roundcube. You should be able to reproduce the problem with openssl s_client from that machine.<br>&gt; It appears that roundcube doesn&#39;t like Let&#39;s Encrypt in a way that neither dovecot nor postfix (nor any of several MUAs) have an issue with<br>&gt;<br>_______________________________________________<br>Roundcube Users mailing list<br><a href="mailto:users@lists.roundcube.net">users@lists.roundcube.net</a><br><a href="http://lists.roundcube.net/mailman/listinfo/users">http://lists.roundcube.net/mailman/listinfo/users</a>