Using IFrame component (vaadin 14)

Hi all,
I’m new to Vaadin, and I’m trying to use, modifiy and combine some examples.
I executed the vaadin tutorial (Building Modern Web Apps with Spring Boot and Vaadin.pdf) and I’m now trying to replace the content with an Iframe, in which I’ll load another application/url. I can load external url (http://www…) and navigate the loading vaadin application without problem.
When the url is another local vaadin application, the application loads fine in the iframe, but if i navigate the loading app, the whole page reloads, and I’m redirected to the login screen of the loading app.
Would anyone have any suggestions to what the problem might be?
Regards

I probably found the problem: a coockie issue: every vaadin application uses a cockie, and if you use multiple vaadin application in the same page, the cookie will be overwritten.
I solved adding property server.servlet.session.cookie.name in application.property file.