More and more clients are getting this error and I'm struggling to find any relevant information. Can someone point me in the right direction? The errors are generating from our Win2008SP2/Exchange2010 server. Full error text below: The Kerberos client received a KRB_AP_ERR_MODIFIED error from the server MAIL02$. The target name used was HTTP/MAIL02.dr.LOCAL. This indicates that the target server failed to decrypt the ticket provided by the client. This can occur when the target server principal name (SPN) is registered on an account other than the account the target service is using. Please ensure that the target SPN is registered on, and only registered on, the account used by the server. This error can also happen when the target service is using a different password for the target service account than what the Kerberos Key Distribution Center (KDC) has for the target service account. Please ensure that the service on the server and the KDC are both updated to use the current password. If the server name is not fully qualified, and the target domain (dr.LOCAL) is different from the client domain (DR.LOCAL), check if there are identically named server accounts in these two domains, or use the fully-qualified name to identify the server. Outlook seems to freeze or lockup around the times that this error is reported. The server is an Exchange server, so I'm afraid to unjoin/rejoin the domain. There is very little else out there for solutions. Any help will be greatly appreciated.

Just to follow up, I've checked for dupicate IP's in the network and verified DNS is pointed at the correct server. I'm out of ideas. Thanks.

Are you using NLB? Please see this KB. http://support.microsoft.com/kb/558115

We are not using NLB. We do have an exchange environment that had two servers for a short time, but the old one has been decommissioned. Could we have some cleanup that still needs to happen?

More information, when I open Outlook and monitor the connection status, I see referrals to connect to the old exchange server. They fail repeatedly for about 10 seconds, then the event is logged afterward. I definitely think this is part of the problem.

run scavanging on your dns server.

DNS scavenge doesn't seem to have helped.

Did you run sysprpep on the computers in question. Is it possible that computers are build from image that is not syspreped?

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