When I register I don't receive the registration email. I have no problems with joomla registration including mass mail, an CB registration using php-mail My Joomla Global configuration:

public $mailonline = '1';
public $mailer = 'smtp';
public $mailfrom = 'server@mydomain.com';
public $fromname = 'My web title';
public $sendmail = '/usr/sbin/sendmail';
public $smtpauth = '1';
public $smtpuser = 'server@mydomin.com';
public $smtppass = '*****';
public $smtphost = 'localhost';
public $smtpsecure = 'none';
public $smtpport = '25';


In debug I receive this error.

Warning: stream_socket_enable_crypto(): SSL operation failed with code 1. OpenSSL Error messages: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed in /var/www/vhosts/xxxxxxxxxxx.com/httpdocs/libraries/CBLib/CBPHPMailer/CBSMTP.php on line 371

I don't know what is the problem because my SMTP security is none (No SSL or TLS)

Could you help me please?

Hi, I have Lets Encrypt on my server. I don't have an option to add a mail record like smtp.domain.com to the certificate. Normally I just send through SMTP either using localhost, or the server's default mail domain.

I have lots of components with various advanced mail settings and have never run into this issue before.

There must be another solution to avoid this error?

PHP 7.1.13
CB - updated today
J! latest
Using SMTP mail config in Joomla with authentication
HTTPS certificate, yes.

I can't seem to get this right. Certificate is up to date. Domain/ host names match. I even receive the test mail from Joomla. Just the CB mails don't come through.

We do not want to use PHPMailer.