One of our users has a strange sync problem with Outlook 2007 (on Exchange), latest ActiveSync and an iPaq.

When he logs-in everything works, unread e-mails are sync'ed, but after that it doesn't. You can see the sync icon go on the iPaq but it doesn't retreive any new e-mails. I thought I'd fixed it by getting Outlook to recreate the OST file, and it worked for a while, new e-mails were sync'ed fine. But I've just had an e-mail from him saying it's stopped working again!

Can anyone help?