We run a Hosted exchange network with Exchange 2010 Standard (SP1 RU6).
Last friday we started getting reports that Office 2007 users where getting the 0x80004005 error when trying to send emails.
We tried setting up the clients again using a new Outlook profile without success, today we also managed to reproduce the issue reliably using XP Pro SP2 and SP3 with Office 2007 SP2 and 3.
We have contacted Microsoft for assistance but so far without any luck so far.
All the users can send emails using OWA and the error gets synced to the server.
What we have looked at so far:
http://social.technet.microsoft.com/Forums/da-DK/exchangesvrgeneral/thread/08c4350f-7bad-47b6-94a4-a85b50776785 (we tried rebooting the exchange servers, no change)
http://forums.techarena.in/small-business-server/804140-2.htm (My colleague who tried this, no change)
Microsoft suggesting updating from SP1 to minimum RU3, preferably RU6, no change.
Microsoft suggested looking at the AV on the server, in our case we removed all AV due to a different bug at OS level causing it to freeze up, so no AV interferring in this case.
We have looked at the network at our customer, but since we manage to reproduce it reliably, also locally (servers are virtualized, created a VM and reproduced issue there) we have ruled out networking issues.