Magento 2 hide section in admin panel

Question

How do you hide a default magento 2 config section in the backend (Admin Panel)? For example I want to hide the "Mail Sending Settings" section located in Stores->Configuration->Advanced->System

This is what I tried so far but it's not working:

composer.json

{
"name": "vendor/module_name",
"description": "SMTP Extension for Magento 2 to help the configuration of the SMTP (Simple Mail Transfer Protocol) server.",
"type": "magento2-module",
"version": "1.0.0",
"require": {
    "php": "~5.6.5|7.0.2|7.0.4|~7.0.6",
    "magento/framework": "100.1.*",
    "magento/magento-config": "100.1.*" 
},
"license": [
    "proprietary"
],
"minimum-stability": "stable",
"autoload": {
    "psr-4": {
        "Vendor\\Module_Name\\": ""
    },
    "files": [
        "registration.php"
        ]
    }
}

registration.php

<?php

\Magento\Framework\Component\ComponentRegistrar::register(
    \Magento\Framework\Component\ComponentRegistrar::MODULE,
    'vendor_module_name',
    __DIR__
);

etc/system.xml

<?xml version="1.0" encoding="utf-8"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
    <system>
        <section id="system">
            <group id="smtp" showInDefault="0" showInWebsite="0" showInStore="0">
            </group>
        </section>
    </system>
</config>

etc/module.xml

<?xml version="1.0" encoding="utf-8"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="vendor_module_name" setup_version="1.0.0">
    </module>
</config>

PS: My cache is disabled and my Magento 2 installation is in developer mode.

Answer 1

After some trials and errors I finally figured why it wasn't working. The file system.xml was misplaced into the wrong folder. system.xml needs to be placed under etc/adminhtml/system.xml and NOT under etc/system.xml.