Server-side Includes don't get included - help needed

Hi there,

my SSIs are in the Design view and the Preview mode but NOT in the Open in browser view.

I use an Includes directory and have tried to place the include in the same directory like the pages. No difference.

Any ideas what is missing here?

Thanks

Joerg

<!--#include file="includes/_header.html" -->

<main>
	<div class="row">
		<div class="col">
			<h1>Index</h1>
		</div>
	</div>
</main>
<!--#include file="footercopy.html" -->