I can provide you this documentation about vartical-align.
You should understand, that you need some elements, like a picture, for to see some difference. Or you wanna get smthing another? Draw your expected output.
Also read this answer
My working example needs white page
, because it was also not working as your page. The problem is in predefined project stuff. Find yours which doesn't allows you use this solution
<body>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
<div class="container h-100">
<div class="row align-items-center h-100">
<div class="col-6 mx-auto">
<div class="jumbotron text-center">
<h1 class="display-4">Jumbotron</h1>
<p class="lead">This is a simple centered hero unit.</p>
<p class="lead">
<a class="btn btn-primary btn-lg" href="#" role="button">Learn more</a>
</p>
</div>
</div>
</div>
</div>
<style>
body,html {
height: 100%;
}
</style>
</body>