[Module] Let's Encrypt

[Bizarrus]

You can check the log files. With no informations, i can't help out.

Which apache modules are installed?

My first thought: open basedir restrictions

On simple test with an online sandbox (http://sandbox.onlinephpfunctions.com/) with PHP 5.6.29, i've got following error:

Warning:  dirname() has been disabled for security reasons in [...][...] on line 2

And i think, that's the problem. I will try to solve these for older PHP versions.

Can you try to modify following lines to solve the problem?
/etc/sentora/panel/modules/letsencrypt/code/controller.ext.php

PHP Code:

// From
require_once(dirname(__FILE__, 1) . '/ACMECert.php');
require_once(dirname(__FILE__, 1) . '/TLD.php');
require_once(dirname(__FILE__, 1) . '/LetsEncrypt.php');

// To
require_once('ACMECert.php');
require_once('TLD.php');
require_once('LetsEncrypt.php');