Hi @[deleted] ,we use SMTP.I was looking for solution and find something like this:go to include/pear/Net/SMTP.phpchange if ($tls && version_compare(PHP_VERSION, '5.1.0', '>=')toif ($tls && version_compare(PHP_VERSION, '6.1.0', '>=')turn on Authentication Requiredand it working for my SMTP server.Thank, we can close it.Rafal