Outlook 2016 and Exchange Online Repeated Credential Prompt

Occasional Visitor



We have few users outlook is continiously prompting for credentils ,


We have installed latest O365 version

its working fine on OWA

we have tested that users in different versions like windows 10 and windows 7 machines with latest office

and also we did some changes as per online in registery as below




can some pls help on this 


O365 syncs from AD and all the mailboxes are in O365 now.


1 Reply

Hello @Ramesh Vemavarapu,


For me when this happens, 95% of the time there are permissions for that user somewhere.


So if Dan is always getting credential prompts on his outlook, there is a good chance Dan has permissions to some other users mailbox that is not registered properly. Especially if those permissions are still to an old on-prem user.


Try checking both your hybrid exchange and o365 for permissions this user may have. If they are old/unused clean them up.