This symptom is intermittent and I am stumped where to troubleshoot. Clients (outlook 07) will occassionally fail to connect and re-prompt for cred's. If you right click + control and look at connect status, the Excnage server shows FAILED. If I click reconnect several times it dosent cycle through DC's like it does when its healthy. I am convinced this is a network issue.... EX07 is running a NIC team and also has a separate VLAN on an additional NIC for server management that is used on a separate VLAN. I show no errors, server side that indicate this issue. IT acts like a session's credentails black-holes itself and times out with no reply. After a few minutes it is back to connecting healthy and no particualr DC seems to be the culprit.

HAve you run ExBpa against the server? Latest NIC drivers installed? What is the O/S?

Any update on the issue Gotwings?Jonas Andersson MCTS: Microsoft Exchange Server 2007/2010 | MCITP: EMA 2007/2010 | MCSE/MCSA Blog: http://www.testlabs.se/blog

Hi Gotwings, Please follow AndyD's suggestion, and then use OWA to check the account's mailbox. Then we could narrow down the issue, if the EXBPA report no issue, and OWA work well, I think it would be caused the network issue. Please check the client whether it could connect the needed port of the exchange server. Regards! Gavin

Hi Gotwings, Please follow AndyD's suggestion, and then use OWA to check the account's mailbox. Then we could narrow down the issue, if the EXBPA report no issue, and OWA work well, I think it would be caused the network issue. Please check the client whether it could connect the needed port of the exchange server. Regards! Gavin @Andy EXBPA is run regularly and is clean. This is a smallish SCR (sp2) environment. Sounds good guys. Problem has been night shift is the busiest time, and I will just get an email and a error screen shot the next morning. Theres no rhyme or reason to who and where this pops up. I turned outlook logging on a few admin machines in case they get the error. To my knowledge OWA hasnt had ANY issue, including this Here's what I will do if I get a call: -ping mail server and DC listed in 'Connection status' of Outlook -try to access same mailbox by OWA right then The only oddity I see is that they have a DC with 1 teamed NIC and a second NIC on a separate management VLAN. But the intermittent nature is SO FRUSTRATING-gotta say I have spent hours looking at settings and testing to flush out this issue!!

What is the O/S on the servers?

What is the O/S on the servers? All are 2003 with latest hotfixes and Exchange is SP2 w rollups

Ok, just ensuring that this wasnt a SNP issue with 64 Bit 2003 and Exchange per: http://support.microsoft.com/kb/948496 But ExBpa should have flagged it if those settings were still enabled. Still would look at the NIC drivers and ensure they are updated to latest, and ensure that DC doesnt have 2 different gateways assigned to the NICs or somethign whacky like that. You may to look at wireshark and also increase diag logging within Outlook so that the failures will be recorded in the event log on the clients.