mail cannot connect to incoming/outgoing server

[bob brown]

I use outlook 2002 with a private domain mail server.
the incoming and outgoing servers are pop3. the problem
is, when I keep Outlook active, after a few minutes it
will not send or receive mail. The error message I get
says cannot connect to incoming or outgoing server. If I
reboot, thinks work fine for about ten to twenty minuets.
Any suggestions?
..