I have a user who has access to a few mailboxes as well as shared calendars, and every once in a while she gets prompted for her credentials.  If she puts them in it goes away for a while, she can also cancel out of the prompt and everything works fine.  The prompts usually pop up while she's working in another program, then when she goes back to Outlook it's there waiting for her.

We've already deleted her ost file, rebuilt her Outlook profile, but it's still happening.  her Outlook connectivity says she's connected to everything ok.

any ideas on how to fix it?

Hi,

We have a forum article about this issue:

https://social.technet.microsoft.com/Forums/en-US/bcd2d9c2-1a1b-4446-bf32-69fee8cdf11b/why-does-outlook-keep-prompting-for-password?forum=outlook

You can try some steps in this article to fix the problem, especially make sure Outlook is using NTLM Authentication.

Regards,

Melon Chen
TechNet Community Su

Hi,

Just checking in to see if the information was helpful. Please let us know if you would like further assistance.

Melon Chen

Forum Support