Connecting to ucs from remote, umc returns a blank page



I am running several virtual hosts. Root directory is /var/www/. Startpage is empty. All domains have the root directory at /var/www/domain. I left all settings for univention as it was. /var/www/univention. Apache is set up at /etc/apache2/sites-available with sites enabled. I can reach all domains and the cms are working perfect. I use SSL redirect.
On localhost I can connect to UMC and see the portal or login page as I request.
From remote either with IP-address or I am getting as response a blank page with the following source-text:

<!DOCTYPE html>
<html xmlns="">
		<title>Univention Management Console</title>
		<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
		<meta http-equiv="X-UA-Compatible" content="IE=edge" />
		<meta name="viewport" content="width=device-width, initial-scale=1">
		<link rel="shortcut icon" href="/favicon.ico" type="image/x-icon" />
		<link rel="stylesheet" href="/univention/management/style.css" type="text/css"/>
		<link rel="stylesheet" href="/univention/js/dijit/themes/umc/umc.css" type="text/css"/>

		<script type="text/javascript" src="/univention/js/config.js"></script>
		<script type="text/javascript">
			//<!-- = {
				'*': {
					'umc/app': 'management',
					'umc/modules': 'management/modules'
			umcConfig.callback = function() {
				require(["umc/dialog", "umc/tools", "dojo/json", "dojox/html/entities", "umc/i18n!management"], function(dialog, tools, json, entities, _) {
					setTimeout(function() { /* dependency problem umc/dialog is not yet require()d in umc/tools*/
						var data = json.parse(entities.decode("{&quot;status&quot;: 404, &quot;message&quot;: &quot;The path '/portal' was not found.&quot;, &quot;traceback&quot;: null, &quot;location&quot;: &quot;;}"));
						var info = tools.parseError(data);
						var title = info.title || _('HTTP Error %s', info.status);
						var traceback = info.traceback || '';
						var message = info.message;

						var error_message = title + '\n' + message + '\n' + traceback;
						tools.showTracebackDialog(error_message, message, title).always(function() {
							setTimeout(function() {
								window.location.href = data.location || '/univention/management/';
							}, 1000);
					}, 1000);
		<script type="text/javascript" async src="/univention/js/dojo/dojo.js"></script>
	<body class="umc umcOverviewShown">
		<div id="umcTopContainer" class="umcTopContainer"></div>
			<div class="warningWrapper">
				<div class="warningCenterer"></div>
				<div class="warning" id="no-js">
					<div class="icon"></div>
					<div class="title">JavaScript required</div>
					<p>A browser with JavaScript enabled is required in order to use this service.</p>
					<p>When using Internet Explorer, please check your security settings and add this address to your trusted sites.</p>

Where do I have to correct redirect settings? Or what else is wrong?