vaadin / session expired everytime

Hi all, i need help for a problem that is going to make me crazy :frowning:
I’m using Vaadin 7 for a web application that calls external rest services.
every time I start the application, at the first access i get “Session expired” without sense cause it appears immediately.
When i call some services that need some minutes to work, again i get that “Session expired”.
I tried with:

  • vaadin.servlet.heartbeat-interval=-1
  • server.session.timeout=6000000
    but doesn’t work…
    Moreover i inserted in web.xml -1
    again it doesn’t work…
    Can someone help me? this Vaadin session becomes to be enervating!

I forgot to say that i tried with setMaxTimeout() of UI.getSession but it doesn’t work anyway…