app/views/errors/service_unavailable.html.erb
<h1><%= title "Service Unavailable" %></h1>
<div class="row">
<div class="col-xs-10 col-sm-6 offset-xs-1 offset-sm-3">
<div class="card my-5">
<div class="card-body">
<i class="far fa-4x fa-exclamation-circle float-end"></i>
<h4 class="card-title">Service Unavailable</h4>
<h6 class="card-subtitle mt-2 mb-3 text-muted">The service is unavailable at the moment.</h6>
<p class="card-text">Please wait and try again in a few minutes.</p>
</div>
</div>
</div>
</div>