Problem connection POP3 sometimes timeout

[Rene Marticke]

hi,

I've got an installation of of kolabsystem where to following error occurs.
Sometimes while putting "Send/Fetch" in Outlook express or Outlook 2003 
the server timed out.
There is no load on the system. Just 1 Testaccount. Sometimes 20 
connections work and then .... timeout.
In the pop3 log there is only the connect line. Connection is 
established but no transfer.

Can you give me some hints how to locate this problem.
Server is Kolab 2.0.3

Best Regards
Rene