How to send an email from a form on a website in Bitrix?

Question

1C-Bitrix

I want to send a letter using PHP Mailer, please tell me what is the reason, I can’t send a letter from the form on the site hosted on Bitrix, I suspect that there is something with the paths in the php file. Data from the form is taken using js. Further sending should be carried out through php mailer, but an error occurs (in the screenshot).