Why might an email not be sent when registering from checkout?

Question

1C-Bitrix

Hello! In the settings of the sale.order.ajax component, "Place an order with automatic user registration:" and "Send a letter to the user that he is registered on the site:" are selected. Registration occurs, but the registration confirmation email (NEW_USER_CONFIRM event) is not sent. In the main.register component, everything is standard. I'm trying to send via PHP-console Bitrix - everything is ok.
To check, I replaced sendImmediate() in main.register with CEvent::send() - also not. b_event is empty.
The event and templates are active and tied to the site. Where else could the problem be?