Ispconfig webmail can send email, but from PHPMailer cannot connect to smtp

Hi,
I have installed ispconfig , webmail is working .
But when i am trying to send email from phpmailer.. i got :

Code:

PHPMailer\PHPMailer\Exception Object
(
    [message:protected] => SMTP Error: Could not connect to SMTP host.
    [string:Exception:private] =>
    [code:protected] => 0
    [file:protected] => /var/www/clients/client1/web2/web/vendor/phpmailer/phpmailer/src/PHPMailer.php
    [line:protected] => 2146
    [trace:Exception:private] => Array
        (
            [0] => Array
                (
                    [file] => /var/www/clients/client1/web2/web/vendor/phpmailer/phpmailer/src/PHPMailer.php
                    [line] => 1970
                    [function] => smtpConnect
                    [class] => PHPMailer\PHPMailer\PHPMailer
                    [type] => ->
                )

Here is my server data:

Code:

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.3 LTS
Release:        20.04
Codename:       focal

Code:

PHP 7.4.25 (cli) (built: Oct 22 2021 12:34:33) ( NTS )
Copyright (c) The PHP Group
Zend Engine v3.4.0, Copyright (c) Zend Technologies
    with Zend OPcache v7.4.25, Copyright (c), by Zend Technologies

 

I have installed ispconfig based on url https://www.howtoforge.com/ispconfig-autoinstall-debian-ubuntu/
My smtp host is mail.ddcart.com , smtp port is 25..

 

I have tested debug on phpmailer , and i got this :

i am set on phpmailer :
$mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
$mail->Host = 'smtp.gmail.com';
$mail->Port = 587;
and got result below :

Code:

2021-11-13 04:58:51 SERVER -> CLIENT: 220 server3.appindowebcity.com ESMTP Postfix (Ubuntu)
2021-11-13 04:58:51 CLIENT -> SERVER: EHLO localhost
2021-11-13 04:59:13 SERVER -> CLIENT:
2021-11-13 04:59:13 SMTP ERROR: EHLO command failed:
2021-11-13 04:59:13 SMTP NOTICE: EOF caught while checking if connected
SMTP Error: Could not connect to SMTP host.
SMTP Error: Could not connect to SMTP host.
Message could not be sent. Mailer Error: SMTP Error: Could not connect to SMTP host.

 

I mean phpmailer config is :

Code:

$mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
$mail->Host = 'mail.ddcart.com';
$mail->Port = 587;

and got result :

Code:

2021-11-13 04:58:51 SERVER -> CLIENT: 220 server3.appindowebcity.com ESMTP Postfix (Ubuntu)
2021-11-13 04:58:51 CLIENT -> SERVER: EHLO localhost
2021-11-13 04:59:13 SERVER -> CLIENT:
2021-11-13 04:59:13 SMTP ERROR: EHLO command failed:
2021-11-13 04:59:13 SMTP NOTICE: EOF caught while checking if connected
SMTP Error: Could not connect to SMTP host.
SMTP Error: Could not connect to SMTP host.
Message could not be sent. Mailer Error: SMTP Error: Could not connect to SMTP host.

 

Like @Jesse Norell wrote:

Use Internet Search Engines with

Code:

test smtp server with telnet