The conection to the server was unsuccessful

The application Error

The conection to the server was unsuccessful (file://android_asset/www/index.html)

Was caused by a script being inaccessible during the page load..

For me changing:

<script src="http://oldplace:8080/target/target-script-min.js"></script>

To

<script src="http://newplace:8080/target/target-script-min.js"></script>

Fixed it