Remember this? http://blogs.flaphead.dns2go.com/archive/2007/11/13/exchange-2007-msexchangeis-9646.aspx
Interesting how HP has hidden this .. I like the final words .. “The real fix is to make sure the network card supports the new featured offered in SP1 and SP2 of Windows Server 2003. Consult the manufacture of the network card for updated drivers. ” BUT THAT IS YOU HP!
Exchange 2007 Standard. No service pack. Window 2003 Standard SP1
Customer had a single user that can not connect to the Exchange 2007 server using Outlook. He could use OWA and connect successfully. He tried using OL 2003 and 2007 with the same error. When trying to use auto discovery after he is prompted for credentials he would get error:
There is a problem with the proxy server’s security certificate. The name on the security certificate is invalid or does not match the name of the target site Outlook is unable to connect to the proxy server (Error code:0)
When he manually configures Outlook and gave credentials he would get error: Cannot open your default email folders. You must connect to Microsoft exchange with the current profile before you can synchronize your folders with you offline folder file.
Customer moved the mailbox to another server. This broke OWA. We then removed the exchange attributes of the mailbox by doing a remove in Exchange 2007 console. After reconnecting the mailbox OWA worked again but we still had the same problem as before. We also notice this error in the event log:
Event Type: Error
Event Source: MSExchangeIS
Event Category: General
Event ID: 9646
Description: Closing Mapi session “/o=Organization/ou=Administrative Group/cn=Recipients/cn=Recipient” because it exceeded the maximum of 32 objects of type “session”.
This would suggest a third party program making too many connections but this was not the case. The problem was with the network card and is described in this article although the errors we got were not documented.
With the release of the Scalable Networking Pack that is included with Windows 2003 SP2, we in Exchange support have been seeing some connectivity issues once the new networking features are enabled. These new features are enabled by default and are only used if your network card driver supports them. Some of the new architectural additions that were introduced with the Scalable Networking Pack are TCP Chimney Offload, Receive-side Scaling
To Disable TCP Chimney, Navigate to the following registry key and set the value to 0. Note: You have to reboot the server after this registry change.
The real fix is to make sure the network card supports the new featured offered in SP1 and SP2 of Windows Server 2003. Consult the manufacture of the network card for updated drivers.