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outlook 2016 client not accepting credentials

we have a single exchange server with clients running outlook 2016 locally.

everything has been working fine, but now we have one of users who is asked for credentials each time he runs outlook. when we enter the credentials name@domain.local with the correct password, this is not accepted.

if we cancel the windows security window we get the “need password” notice displayed in the bottom right task bar.

mail still seems to flow though??

we can connect using owa using the same credentials.

the option to prompt for credentials is not enabled.

if i try to add another profile the credentials are again refused.

as this does not affect anyone else, i suspect it may not be a server issue, but i am struggling to identify where the problem is.

can anyone help trap this problem?

many thanks

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Last Comment

8/22/2022 - Mon
Sajid Shaik M


check the event viewer.... if there any logs...

run the windows updates and office updates... then check..

all the best


what happened if you run Outlook in safe mode?  Outlook.exe /safe


in safe mode it is exactly the same.

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Walt Forbes

On the workstation in question go to Control Panel>Credential manager>Windows Credentials
Remove all vaults(passwords) in there
Close outlook>Restart Outlook in safe mode and when the credential pop up comes again, log in with his credentials and password and put a check in "Remember Credentials"
Jackie Man

Remove antivirus / internet security software. Then, restart computer.

Repair MS Office installation and try again to see whether the problem is solved.

sorry for the delay. i will update this incident over the weekend, when i will have access to the workstation.

many thanks
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ok i have now tried

1). resetting the user password and restarting the workstation.
2). removing all of the credentials and restarting outlook in safe mode
3). creating a new profile

none of these have helped

i am reluctant to remove the avast cloudcare at the moment, as others are using exactly the same setup without problems.

i have read about an outlook 2016 update which causes this, but im unsure how to roll this back to test.

any suggestions?

when i add a new profile we get to the part that is searching for the user ie user@domain.co.uk and the credential box pops up. when i add the credentials ie user@domain.local and the correct password, it does not accept this here and i cannot get past this point?

does this provide any further help?

Your help has saved me hundreds of hours of internet surfing.

still have the same problem here. it only affects one user and the situation arises no matter which computer he logs on with. owa works fine. this account had worked fine till a couple of months ago.

i have removed office completely, removed the workstation from the domain, re connected, re installed office 2016, but still the same.

i have created a new profile and it identifies the correct email account for the user but when it goes through the searching for your mail server settings, it establishes a network connection - tick, then on searching for user@domain.co.uk it pops up the windows security box headed MAIL APPLICATION
connecting to user@domain.co.uk and asks for credentials.

i have tried user@domain.local and user.domain.co.uk with the correct password, but it just pops straight back up and will not proceed past this point.

its driving us crazy as if we cancel it, it completes ok, but every time we open outlook, the credential box pops up each and every time. if we drag it out of the way and just leave it, everything works just fine. ie we can send and receive email just fine.

as i said, it only affects this one user, but on any workstation on our network.

i have checked through the things previously offered but it has not brought about a resolution.

does anyone have any other suggestions on how to bottom this?

any advice much appreciated.

many thanks

Enter user id and password in the form of domain\user, save the password and check
Jackie Man

A corrupted antivirus or internet security software will definitely cause your symptom.

If you do not try, you will never know.
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many thanks. however, i have tried it on 2 different computers, and the problem is the same.

if i logon as a different user, i can access their email without problem.

i cannot get a clean install of a new outlook profile for this particular user, for some reason, it just will not accept the credentials.

many thanks for your help, its much appreciated.

Do you have roaming profiles ?


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James Murphy


Did you run the Outlook diagnostic utility? any useful information found from that?. I have seen same issue several times but same issue with different solutions been applied. One of the main reason would be related some registry keys. Look at the EE thread which discussed previously and see my comment which worked. I hope this works for you as well

Michael B. Smith

Did you figure this out?

I see that Exchange is on-premises. Is Outlook from MSI or from Office 365 Pro Plus?

so sorry guys, i got drawn onto other more pressing issues.

i have not resolved this issue yet, but will review the whole thing and update the post asap.

the client is working, as by leaving the logon box open, and dragging it out of the way, all is well.

we do still need to resolve it though.

thanks for your patience.
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