I have 3 Exchange accounts in Outlook 2013 and Windows Security is constantly asking for log in credentials despite entering correct password and being able to log in fine with same credentials.

After daily reboot it is only one account that is affected but it is a different account each day.

Any ideas greatly appreciated.

Outlook is working fine even despite the requests for credentials even if these are cancelled.

There is only one user

Hi,

Since this issue is only with one user, I suspect the user's credential has been corrupted.

Please go to Control Panel -> User Accounts -> Credential Manager -> Windows Credentials -> Find and remove the credentials for Outlook, then check the result again.

For the issue "Outlook keeps prompting for password", there is a forum article talking about it, for your reference:

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

Regards,

Melon Chen
TechNet Community Su