Outlook continually prompting for username and password

When it comes to Outlook prompting for user name and password , it is one of the most annoying Exchange issue. imagine when exchange support team gets call for it, how much pain it gets started, they start thinking multiple scenarios where could be the issue, i am trying to cover all the topic where we generally look and resolve issue,

i will be starting what if scenarios, One user , Multiple users and all the users,


Scenarios 1:- what if one user is getting password prompt,

if user can login to owa then try to reboot the outlook,

Make sure password hasn’t expired

Ensrue users are not lock out

Rename the  .ost file and check

Create a new outlook profile

Upgrade to the latest version can fix outlook connection problem

We experienced this some in our environment as well. We found some invalid credentials were saved or corrupt and had to clear them out. Here was the process that we used:

1. Go to Control Panel ==> User Accounts ==> Manage your credentials

2. Under Generic Credentials you will see your Outlook Saved Password. My belief is the password saved in this area is invalid. Remove the saved password and log on to Outlook.


Scenario 2:-

Multiple users getting password prompt in outlook,


1) Check if all the users belongs to one same database , if yes then check database health status, (Database related issue ans their resolution will be updated soon)

2) check if all the user belongs to same domain if you have multiple domain scenarios, if it has all the issue with specific domain then here are the checks to look at,

check if specific domain’s CAS server has enough C drive Space

When doing health checks for Client Access Servers it is important to consider the following components:

Access performance
Hardware performance


Exchange Remote Connectivity Analyzer

Test-EcpConnectivity- http://technet.microsoft.com/en-us/library/dd351282.aspx

Test-OutlookConnectivity- http://technet.microsoft.com/en-us/library/dd638082.aspx

Test-OutlookWebServices- http://technet.microsoft.com/en-us/library/bb124509.aspx

Test-WebServicesConnectivity- http://technet.microsoft.com/en-us/library/aa998328.aspx


3) Check the event log to see if any specific Domain controller is having issue, login to that DC and do health check, if Event viewer tell it has the issue then reboot the DC,


4) See if any CAS server got removed from NLB or HLB or DNS record.

5) Check problematic user connection from which CAS server and how many connection each CAS has  by below command

Get-Counter  “MSExchange RpcClientAccessUser Count”  -ComputerName CAS_Server

Timestamp CounterSamples
——— ————–
3/28/2017 9:20:08 AM \CAS server\msexchange rpcclientaccessuser count :1687


Get-LogonStatistics -Identity UserName | where {$_.applicationid -eq “Client=MSExchangeRPC”}| fl

5) check problematic user outlook Connection status and check if any connection is connecting or failed or all established, if all established then all good. you can refer blow link to check status.


6) Do IISRESET /noforce or recycle Application pool to reestablish all connection.


If all user or multiple users getting password prompt.

Kernel authentication Mode
The virtual Directories we will be looking for are:


Locate virtual directories for above.

DISABLED for Anonymous authentication

Select Windows authentication, click ADVANCED SETTINGS, select ENABLE KERNEL-MODE AUTHENTICATION. Click OK.

Go to command prompt, run IISRESET.




Check AutoDiscoverServiceInternalUri is set same name on all CAS server.

browse https://autodiscover.Domain.com/autodiscover/autodiscover.xml

SAN and UCC name must contain below

owa.domain.com (the URL used for Outlook Web Access)
servername.domainname.local (the internal FQDN of Exchange Server)
servername (NETBIOS Name of Server)

Change the default Application Pool run account to ‘Network Service’.
Microsoft KB2990117

Verify Outlook Anywhere is configured correctly:

Get-OutlookAnywhere | Select-Object -Property SSLOffloading,ExternalHostname,InternalHostname,ExternalClientAuthenticationMethod,InternalClientAuthenticationMethod,IISAuthenticationMethods

Verify that the correct OAB is used for every Mailbox Database.


Authentication Mode:- Usually this indicates an incorrect setting in IIS. If on Exchange 2007 or newer, I would check the Integrated Windows Authentication for Autodiscover.

Internet Explorer Proxy:- Check if any proxy has been enabled for Client IE


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