Exchange server unavailable

[aputty]

We have an XP client computer which has Outlook 2000 installed. Every time the user logs back on from lunch he receives the following error message:

Your Microsoft exchange server is unavailable.

You can retry connecting to the server using the network, or work offline and connect using dial-up networking.

The network did not respond in a timely fashion to determine the existence of an exchange server, you may retry and continue waiting for a response or work offline.

He selects retry and is then fine. This only happens when the users is logging off and back on again during the day. Not first logs on in the morning

Please help!!

 

[Guest_imported]

The pc went into sleep/hibernate mode and the network connection got disconnected.

 

[aputty]

Hello,
Checked Sleep/hibernate mode options. If you log off and then straight back on again it still comes up with the same message

Cheers