Hi, We had experience few days ago that our users are prompted with username and password. If credentials are entered, correctly, it is still the same. We fixed the issue by Restarting the information store. Can anybody help to advise the root cause and ways to prevent it.? Regards,

Hi , Its weird, outlook is keeping prompt username and password, in many cases, its a authenticatin issue,. Please run Exchange BPA to check servers healthy. Also please test on the following page. https://www.testexchangeconnectivity.com/ Wendy Liu TechNet Community Support

Hi , Its weird, outlook is keeping prompt username and password, in many cases, its a authenticatin issue,. Please run Exchange BPA to check servers healthy. Also please test on the following page. https://www.testexchangeconnectivity.com/ Wendy Liu TechNet Community Support

Is it internal or external what i mean by that is your outlook configured for MAPI Profile or Outlook Anywhere? AS Wendy said it is possible a Authentication issue. Is it just happening to one user?Where Technology Meets Talent

Did this just start? Did you run an RU and then saw the error start? Was there a client version change? Is it all people or just a few?

Here's another hint. The issue re-appears and what we just did is to stop System Attendant service and prompting of credential disappear and service resume to normal.

Hi, Check in the event eventvwr anything helps you. else check the PF. or check owa. Try to drill down where is the culprit. Regards MuthuThanks Muthu

Thanks for the reply. Are you linking to Authentication/Permission issues.? We don't see any unusual error when the issue is happening. But when we stop the SA, it will resume to normal. However, we we restart SA service, this log will register in Event Log. "Unexpected error The local machine must be a Kerberos KDC (domain controller) and it is not. ID no: 80090339 Microsoft Exchange System Attendant occurred. " Naturally, this server is not a DC. We are suspecting System Attendant is causing the OUtlook clients to prompt username and password. BTW, even if users entered correct username and password, it will not work. Regards, Jhun

It happen to us again. User are prompted for username and password. When we stop System Attendant Service, everything resume to normal.

Hi All, Is there anyone can give relationship between System Attendant, Offline Address Book and Autodiscover?