[Exim] The connection timed out

Hello all

we are running Exim on our server now for about tree weeks. It looks like
mail from hetnet.nl does not always arrive on our machine. Mail is returned
by hetnet.nl to the sender. The error message says:

from: <postmaster@???>
To: <elanda.jongejan@???>
Sent: Tuesday, October 01, 2002 1:46 AM
Subject: Nondeliverable mail


> ------Transcript of session follows ------- bestuur@???
> The connection timed out.

Does somebody know what is going on?

Kind regards,

Bas