GAE Issue

[Christian351 (Christian Lanz)]

My application works fine on the local development server, but when I upload it to google app engine it keeps getting an error and does not start at all.

If I use VaadinServlet instead on GAEVaadinServlet in web.xml; the application starts fine, but can’t handle clicks or something else. There is always a “Communication Error”.

Here are my files:

• 
  web.xml:
  http://pastebin.com/Yq5Z4NcM
• 
  appengine-web.xml:
  http://pastebin.com/8q9Xxd2H
• 
  UI:
  http://pastebin.com/CzhwrA8q
  
  (written in kotlin)
  
  
• 
  One view:
  http://pastebin.com/51S0Se7F
  
  (written in kotlin)
  
  
  

Here the error I receive:

This happens when I replace GAEVaadinServlet with VaadinServlet in web.xml (on every button click):

Please help, I don’t know what to do any more …