Can't send emails from Mantisbt on a Linux Oracle 8 server

[userAnonimo]

After successfully running local tests with mantisbt, configure config_inc.php as follows:
$g_allow_signup = ON;
$g_enable_email_notification = ENABLED;
$g_phpMailer_method = PHPMAILER_METHOD_SMTP;
$g_smtp_host = 'smtp.gmail.com'; # used with PHPMAILER_METHOD_SMTP
$g_smtp_connection_mode = 'tls';
$g_smtp_port = 587;
$g_smtp_username= '***0987@gmail.com';
$g_smtp_password = 'application key;
$g_administrator_email='***0987@gmail.com';
$g_log_level = LOG_EMAIL | LOG_EMAIL_RECIPIENT | LOG_FILTERING | LOG_AJAX;
$g_log_destination = "C:\xampp\mailoutput";

Once the matter was validated, mantisbt was mounted on a virtual machine with Oracle Linux 8 operating system, the respective installation of apache, php, phpjson, mysql was carried out. Upon successfully installing mantisbt, the config_inc.php file is configured again with the difference that the registry path changes:
$g_log_destination = "/var/log/httpd/";
In local xampp it was necessary to configure the sendmail.ini file, in linux what is the procedure or similarity with sendMail for sending emails? Since it doesn't work there, I've been searching the help forums, but I haven't found a solution.
I have installed sendmail under the configuration guide, but I have not been able to get it to work.