Completely stumped here. Our environment has about 2500 users and recently we have been getting complaints that outlook is prompting them to login through out the day. This just seems to be affecting about a dozen people, all in the office. Nothing has changed recently. I ran outlook.exe /rpcdiag and it came back with no errors. But, for some reason it keeps prompting them several times a day to authenticate. Our environment is: 2008 R2 Ent SP1 Exchange2010 SP1 RU7 Outlook 2007 on windows XP There are other users sitting in the same office as these users that are not having problems. These users are also on different DB's. Of course if I take them out of cached mode they work fine.

On Thu, 11 Oct 2012 14:43:47 +0000, Mike Smith43 wrote: > > >Completely stumped here. Our environment has about 2500 users and recently we have been getting complaints that outlook is prompting them to login through out the day. This just seems to be affecting about a dozen people, all in the office. Nothing has changed recently. I ran outlook.exe /rpcdiag and it came back with no errors. But, for some reason it keeps prompting them several times a day to authenticate. > >Our environment is: > >2008 R2 Ent SP1 > >Exchange2010 SP1 RU7 > >Outlook 2007 on windows XP > >There are other users sitting in the same office as these users that are not having problems. These users are also on different DB's. Of course if I take them out of cached mode they work fine. If Outlook is configured to use RPC-Over-HTTPS and the client loses connectivity to the CAS (even momentarily) you'll get a logon dialog if you have only "basic" authentication enabled on the CAS. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

Hi Mike, that actually happened to me several days ago :) at my organization, the problem was because the OAB not accessible via client outlook thats why it keep on prompting the password, because outlook tried to download OAB, and it failed then if you disable the cache exchange mode, outlook wont access OAB, but will directly user address book on server, thats why it work fine maybe you can test your OAB via download it manually on problematic outlook if it failed, its likely because of that

Bhaskoro the users arent getting any sync errors. If I download the OAB manually keeping "Download changes since last send / receive" checked and keeping full details checked no errors. No errors either when I uncheck "Download changes since last send /receive". Rich excuse my ignorance but how do I check if only basic authentication is enabled on the CAS ? On a side note it seems the only common denominator that I see right now between all the users when I run echo %logon server% is that they are all authenticating to the same DC. Which when going through the eventvwr has quite a few netlogon errors saying couldnt setup a secure connection with a domain controller.

On Fri, 12 Oct 2012 12:45:20 +0000, Mike Smith43 wrote: > > >Bhaskoro the users arent getting any sync errors. If I download the OAB manually keeping "Download changes since last send / receive" checked and keeping full details checked no errors. No errors either when I uncheck "Download changes since last send /receive". > > > >Rich excuse my ignorance but how do I check if only basic authentication is enabled on the CAS ? You can use these cmdlets: Get-OutlookAnywhere Set-OutlookAnywhere >On a side note it seems the only common denominator that I see right now between all the users when I run echo %logon server% is that they are all authenticating to the same DC. Which when going through the eventvwr has quite a few netlogon errors saying couldnt setup a secure connection with a domain controller. Only one DC? Not really an Exchange problem, though. Maybe they need to reset the secure channel on the clients? --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

Sorry I didnt get back sooner. But we ended up having a DC fail yesterday. After getting it back online and rebooting all the DC's the issue seems to have disappeared.

Hi , Thanks for sharing your solution, its very useful for us.Wendy Liu TechNet Community Support

No problem. I still believe it was one of our DC's that was having issues. That seemed to be the common denominator, even though we had one or two people that were authenticating to another dc it resolved their issue as well.

Yes , in general, the account will authenticate on local DC first, and if authentication is unsuccessful, there will be event error on Event Viewer in local DC.Wendy Liu TechNet Community Support