After a long research I found a workaround which fullfills my requirements. I've to run this webapplication via HTTPS and with port 443 it works perfectly. I can not explain why there is a problem with the default HTTP port 80, but if I access the webapp through port 443 there is no problem. In addition i tried port 8000 via HTTP und it also works.
Summary:
Port 80 / HTTP --> not working
Port 8000 / HTTP --> working
Port 443 / HTTPS --> working
In conclusion I have an virtual host config for port 80 with a permanent redirct to 443.