Bootstrap vertical alignment not working no matter what : <p>I've read tons of different topics and articles about that common issue but still no working solution. Now I'm kinda desperate so I'd very grateful for any help and here's code:</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-css lang-css prettyprint-override"><code>.auth-tab {
	background-color: red;
}</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;body&gt;
  &lt;div class="container-fluid"&gt;
		&lt;div class="row justify-content-center align-items-center"&gt;
			&lt;div class="auth-tab col-xs-12 col-sm-8 col-md-5 col-lg-6 col-xl-6"&gt;
				sth
			&lt;/div&gt;
		&lt;/div&gt;
	&lt;/div&gt;
&lt;/body&gt;</code></pre>
</div>
</div>
</p>

<p>What I want is to vertically and horizontally align <code>.auth-tab</code></p>
