Embedded Vaadin 404 UIDL POST Requests

Hello,

I’m currently building a Vaadin Application in an Vaadin 8.0 environment.
My problem is that the UI elements are not responding to the user interaction, basically an accordion not opening.
If I interact with an element the Server connection lost, trying to reconnect notification pops up.

I’m not using the original Servlet since there are other Vaadin sites running on the same tomcat container. So my best guess is right now that something in the new Servlet is wrong, so here’s my Servlet code:

@WebServlet(urlPatterns = "/releaseemploye", name = "releaseemploye", asyncSupported = true)
@VaadinServletConfiguration(ui = ReleaseUI.class, productionMode = true, closeIdleSessions = true)
public class ReleaseUIServlet extends VaadinServlet  {
// basicly empty
}

I’m also not quite sure if I would have to add something to the Servlet to make it work properly or if the extend of the VaadinServlet is enough to run the UI.

kind regards