We have the same problem and same design. I have taken to setting up a 2nd OWA with a test SSL certificate to see if this is a hardware or communication issue. So far, the 2nd one seems to outperform the 1st and here is the difference. On the 1st OWA we have anti virus plus it is our smtp gateway so your bound to have problems and I believe this is why the inetinfo goes to 100% The 2nd OWA is running just that, OWA, so if this helps you great. Check the firewall settings between DMZ and NT network, make sure that NETBIOS ports are going bi directional and open just 443 from the internet to the OWA server. The bi directional is because the exchange service account will have to authenticate to the domain controller. I suppose you could restirct this communication to a specific domain controller is you feel this is necessary. Make sure your users turn off pop-up blockers that seems to cause the "failed to get inbox" message. If you can I would recommend setting up the 2nd OWA you might be surprised I'd just like to close by saying that suggesting that people upgrade is perhaps the most ridiculous and frustrating advice to offer. I read this group often and once in a while ask a question. But seriously if you don't have anything constructive to offer don't bother. Helping each other is what this should be about