How to send an email template after registration?

Question

1C-Bitrix

Sending a letter after registration does not work, I tried to tick the box Request registration confirmation by E-mail in the engraving module. But without the original. Letters come by themselves, only after registration for some reason not.
I tried to create an event handler, but I didn’t fully understand how to call the template correctly when sending a letter

/bitrix/php_interface/init.php
AddEventHandler('main', 'OnAfterUserRegister', 'OnAfterUserRegisterHandler');
function OnAfterUserRegisterHandler($arResult){
    $event = new CEvent;
    $event->SendImmediate('NEW_USER_CONFIRM', SITE_ID, $arResult);
}

I have
[email protected] smtpstatus=554 smtpmsg='554 5.7.0 Failed to authorize the sender 1530262234-CxolEfTzew-oXSWvupu 1530262234-iauO80Yiv1-oXvCAgWL' errormsg='the server did not accept the mail' exitcode=EX_UNAVAILABLE

Answer 1

The problem is in accessing the mail that the previous developer indicated