How to make php-js mail arrive?

Question

PHP

I'm trying to set up a feedback form on the site, I came across several tutorials:
lebonnet.ru/ajax-forma-obratnoj-svyazi-php-jquery.html - in this tutorial, when uploaded to the server, everything works (externally) is normal, but the letters don't come
www.sanwebe.com/2011/12/making-simple-jquery-ajax-... - in this tutorial, everything works outwardly on the localhost, it's clear that it won't work to check the mail, but nothing happens on the server after pressing the "send" button. Server on nik.ru
There are several questions:
1. how to check what is the problem? is there a file on the server where such logs are written (there is nothing in the error logs)
2. how to solve?
Thank you!

Answer 1

Are you a programmer or a user?
If the first, you tear off everything from the first tutorial, except for the contact.php file, throw out all the checks in it, enter test data and try to send.
To find out what's the problem with sending.
If the latter, then look for a programmer.