I have installed BorderManager 3.8 (latest patches) and client use
clntrust.exe to authenticate.

When a user visits a webpage, the webpage doesn't fully load. Some pictures
and text is loaded, but then nothing happens. If you press STOP and REFRESH
the webpage is displayed immidiately! So it looks like the BMEE server is
loading the website correctly, but the client doesn't see the results (only
after a refresh).

What can be wrong here?